TL 

La 




EHhMn 
BNpBb 



mMHBB B raffl fl HC fiS 

WBttSSSm 

IfflHnffl 



HSHBB B B fflfflS Hw 
iHIPH 






nnda 



nonvtwRRM 

HSbbseW 




mm • 



HI mi 



HhHHhhS 

R9 



WHJMI 



nana 



■r 



SB 

Ml 



mhhS 

Infl 
BflBM 
■Ml 

■ 



«9 




■JUQ Mil Ikf f IJH1H 



IK 







HHHH 



H« 



Hi 



Hi 
JOB 



MNNH 

■nQaHH 
1MB Hnfi 

IHBitBHBi 
OH 



H 

ffiSffl 







HUM 

if** 



BKBWB 






wYttcK 
[ W W 

Emu 
fiHl 



mm 

IB M 



BH6 
88 
fie 



PRWBM5B 



jhhu 






HH 



iffflDyBBywNMQE&SI 
BMnQBmffi 08088 
HmSMwSRmh 

HShwwBBmKKSuij 






JH 

yffie 



^s 



BftflmMHHgM 








h 
LJ 
Li 
K 
h- 
0) 

I 
h 
u. 

J 

H 
h 

n 
-l. < 

U Hi 

GO 
CO 



c\J 



LEAF SPRINGS 



Their Characterisi 



an< 



Methods of Specification 



A HAND-BOOK OF 

>BILE LEAF SPRtt 
OF SPECIFICATION 
ISTICS, TOGETH 



DAVID LANDAU 

CONSUL"; EER 



[ELDON 

WILK PA. 



COPYRIGHTED 1912 

by the 

SHELDON AXLE COMPANY 

PRICE, $2.00 



/ 



1/7 



€CLA319069 



« 



PREFACE 

The subject of automobile leaf springs has been discussed at 
various times in the technical press, and before engineering soci- 
eties, but never have the more patent facts dealing with their 
details and modes of specification been made an issue. 

There has been a lack of practical data to assist the designing 
engineer in a better understanding of this subject. He has been 
compelled to resort to lengthy correspondence with the spring 
maker and this has resulted, with few exceptions, to mutual 
misunderstanding. The fault lies with the spring maker. He 
has not stated his case. 

It is with the desire that the engineer be given all the infor- 
mation necessary to a complete understanding of the subject of 
leaf spring specifications, that we have attempted here, for the 
first time, to give it the treatment that it deserves. 

The object of the work is to enlighten the engineer as well 
as the user, by elementary and logical discussion of the details of 
construction and the proper form of specification as applied to 
leaf springs used on power-propelled vehicles. 

Impartial treatment has been the aim throughout, and to at- 
tain this end, general statements are made. Whenever it was 
thought that a principle or statement could be made clearer it 
is supplemented by line cuts, and typical examples taken from 
practice. Criticisms have been made in their proper places and 
reasons given therefor. The treatment is thus impartial and, in 
this respect, the present work fulfills the mission of a text-book. 
This will enable the subject matter to be applied, as was intended, 
to the study of any maker's product. 

Owing to the rapid growth of the leaf spring industry in the 
last few years, many new terms have been introduced and the 
meaning of several of the older ones changed slightly. A glossary 



of the more important of these has, therefore, been added at the 
end of the book. This should assist the reader in the more com- 
plete understanding of the spring maker's correspondence. The 
glossary is new and is published for the first time. 

Every endeavor has been made to shed light on some of the 
obscure problems in this branch of engineering and it is the hope 
that future specifications will bear evidence of this work, and 
tlie art, as a whole, may be benefited thereby. 

While this book was in course of preparation several of our 
friends asked us to include a brief description of our plants, or- 
ganization, and processes, and in accordance with their wish we 
have included such a description at the end of the w r ork. 

The Editor cannot too strongly express his appreciation and 
thanks to Mr. William H. Son, Vice-President and General Man- 
ager of the Sheldon Axle Company, who has made this work pos- 
sible. 

A.s a practical investigator he has done much during the past 
quarter of a century to improve leaf springs. He was the first 
to introduce the test data specification sheets for engineers, and 
inaugurate the first spring engineerng staff in this country. 

Acknowledgment is here made to all those who have assisted 
in the preparation of this text and in particular to R. A. Schaaf 
and John B. Kaier of the Spring Engineering Department. 

The Editor has made every effort to have this work free 
from errors and solicits suggestions or criticisms tending toward 
the improvement of subsequent editions. 

SHELDON AXLE COMPANY 

Spring Engineering Department 

David Landau 
Consulting Engineer 



VI 



TABLE OF CONTENTS 



PART I 
Historical Development 



PART II 
Leaf Springs — A Word of Introduction 



PART III 



Leaf Spring Details Page 

Details 4 

Half Elliptic Springs 4 

True Sweep — Double Sweep 4 

Eyes 5 

Bushings 5 

Reaming 5 

Eyes Turned Up or Down, Relative Strength and Advantages 5 

Berlin Eye 6 

Forged Eye 6 

Master Leaf 6 

Long Plate— Short Plate 6 

Spring Seat 6 

Importance of Short Plate Length 6 

Center Bolt Diameters 7 

Eye Bolt Diameters 7 

Special Bead or Nib 7 

Location of Center Bolt . . 8 

Off-Center Springs 8 

Leaf Points 8 

Tapering 8 

Long Plate— Full Thick . . 8 

Wrapper 9 

Alinement of Leaves 9 

Saw and Bead 10 

Ribbing, Strength Only Apparent 10 

Stress Changes Due to Ribs 11 

Lips 11 

vii 



Page 

Lips the Strongest Construction 12 

Clips, Advantages of, in Rebound 12 

Clinch Clips 12 

Bolted Clips 12 

Clips Essential When Driving Effort is Taken by Spring . . 12 



PART IV 

Examination of Materials 

Properties of Wrought Iron 13 

Steel is Wrought Iron Containing a Larger Percentage of 

Carbon 13 

Pennsylvania R. R. Co.'s Investigation of Spring Steels . . 13 

Spring Steel Contains 1% Carbon 15 

Dragon Brand 15 

Carbon Steel No Longer Adequate 15 

Alloy Steels 15 

Standards for Spring Steels 15 

Alloy Steels Do Not Change Riding Qualities 15 

Alloy vSteels Increase Length of Life 16 

Effect of Modulus of Elasticity 16 

Thickness of Spring Steel 16 

3/8 the Greatest Thickness 16 

Advantages of Inch Thicknesses 17 



PART V 

Proper Comparisons of Leaf Springs 

Easy Riding 18 

Car Inspection by Spring Constructors 18 

Endurance 18 

Breakage Produced by Repeated Bending 18 

Steel is Stretched When Under Load 18 

Fibre Stress Explained 19 

Measure of Fibre Stress 19 

Stress is Measured in the Outer Fibres 21 

Stress Varies as Thickness of the Leaf 21 

viii 



Page 

Stress Varies as the Deflection 21 

Stress Varies Inversely as the Square of the Length .... 21 

Stress is Measured Primarily by Shape Only 22 

Requirements Demanded by Long Life 22 

Proper Thickness of Leaf 22 

Proper Deflection 22 

Proper Length 22 

Proper Material 23 

Injurious Deflection of Springs 23 

Elastic Limit 23 

Different Materials Have Different Elastic Limits 23 

Alloy Steels Have Higher Elastic Limits and Ability to Re- 
sist Fatigue 24 

Electric Furnace Silico — Manganese Steel 24 

Heat Treatment of Spring Steel 24 

Relation Between Endurance of a Spring and Its Weight . 24 

Increased Weight Goes Into Life 25 

Proper Spring Lengths for Pleasure Cars 25-27 



PART VI 
i\NALYSIS OF A SPRING SPECIFICATION 

Foreword to Writers of Specifications 28 

Length of a Spring is Variable 29 

Height of a Spring is Variable 29 

Each Variation of Load Changes the Length and Height of 

a Spring 29 

Outside Height 31 

Inside Height — Opening 31 

Proper Way of Specifying Cambers 31 

Number of Leaves and Their Thickness to be Left to the 

Spring Constructor 31 

Matters Effecting the Number of Leaves and Their Thick- 
nesses 31 

Give Total Load Each Spring Must Carry 32 

Springs Obtained by Rule-of-Thumb Method Sure of Event- 
ual Failures . 32 

Loads Must be Definitely Known 32 

Right and Left Hand Loads Desirable 33 

ix 



PART VII 
Suggestions of Methods for Obtaining Weight 

of the Car 

Page 

Loads from an Experimental Model 34 

Freight or Passenger Load Must be in Place When Getting 

Loads and Dimensions 34 

Front End 34 

Rear End 34 

Weight of Right and Left Sides 35 

Weight of Parts Not Supported by Springs 35 

A Typical Case in Detail 35-37 

Check Heights and Lengths with the Assembly Drawing of 

the Car 37 

Note Shackle Position 37 

Analysis of Weights of Greatest Value to All 37 

Other but Indirect Methods of Obtaining Weights .... 38 

First Approximate Method . 38 

The Inaccuracy Caused by Friction of Leaves 39 

Neutralizing Friction Partly by Rapping 39 

A Second Approximate Method 39 

Getting Loads Before a Car Has Been Constructed .... 40 

Method of Balanced Moments 40 

Summation of Moments 40 

A Method Within the Scope of Modern Engineering Depart- 
ments 41 



PART VIII 
Model Specifications for Leaf Springs 

Suggestions for the Preparation of Specifications 42 

We Prefer a Print, Not a Pencil Sketch 42 

Legibility of Figures and Dimension Arrows 42 

Firm's Name on Prints 43 

Number Your Prints 43 

Issue Letters 43 

Specification for a Semi-Elliptic Spring 43 

X 



Details to be Included in Specifications Page 

Width 43 

Lengths, Partial and Total . . 43 

Height or Camber 43 

Height at Each End „ 44 

Level Seats 44 

Inside Diameter of Each Eye 44 

Load on Spring 44 

Oil Holes 44 

Spring Seat 44 

Clearance 44 

Front or Rear, Class of Service . . . 45 

" Plain End" Spring . 45 

Platform Cross 45 

Order Springs in Sets 45 

When Only Cross of a Platform is Ordered Prints of the 

Side Springs Should be Sent 45 

Three-Quarter Scroll Elliptic 45 

"In to Out" Dimension 46 

" Out to Out" Dimension. 46 

Scroll Style and Details 46 

Full Elliptic 46 

Examine Opening Carefully 46 

Double Scroll Full Elliptic 46 



PART IX 

Consideration of Important Details 

Spring Fastenings 47 

Loose Clips Cause Breakage of the Spring 47 

Box Clip Diameters 47 

Shape of Spring Seat 48 

' ' Packing ' ' at the Spring Seat 48 

Strapping Spring With a Third Clip 48 

Pressure Block to Hold Spring at Center Bolt 49 

Car Owner Must Keep Box Clips Tight . . 49 

Level Spring Seats 49 

When Spring Takes the Driving Effort, Keep it Flat ... 49 

xi 



Page 

Do Not Prescribe Thickness of the Scroll Element .... 50 

" Flat Top" 50 

Shape of Springs 50 

Low Camber Gives Better Riding 51 

High Springs Weigh More 51 

• Pounds Per Inch," Stiffness 52 

Relation Between the Various Heights Obtained From the 

" Pounds Per Inch" 52 

Flexibility or Deflection Per Unit Load 53 

A Specification Which Cannot Be Interpreted 53 

Free Height, Together with Stiffness, Not Sufficient . . . 53 
Arbitrary Test Loads Should Not be Given. They Give 

Xo Indication of Riding Qualities 53-54 

Arbitrary Test Loads Do Not Permit Knowing Stress ... 54 

Insufficient Clearance and Its Effect 54 

Bumpers 54 



PART X 

Sheldon Axle Company's Spring Test and 
Data Sheets 

Specification No. 1, Semi-Elliptic 56 

Specification No. 2, Three-Quarter Scroll Elliptic 57 

Specification No. 3, Full Scroll Elliptic 59 



PART XI 



Tin. Sheldon Axle Co.'s Spring Plants and OR- 
GANIZATION 61-64 



PART XII 

Glossary of Terms used ix the Automobile Leaf 
Spring Industry 65-88 



Xll 



PART I 

HISTORICAL 



It is not definitely known who invented leaf or plate springs, 
but history seems to point that shortly after the year 1750 these 
contrivances were popularized by vehicle makers in England, and 
shortly afterward in France and Germany. Their high cost at this 
time prevented their general adoption and we are probably right 
in assuming with Mr. William Bridges Adams, "That wealthy 
men led the way by having coaches built on springs or altering 
their vehicles." 

In the year 1768 Dr. R. Lovell Edgworth succeeded in dem- 
onstrating the advantages possessed by vehicles that were sprung, 
nnd he was awarded three gold medals by the Society of English 
Arts and Manufacturers. 

In the now well known work, "A Treatise on Carriages and 
Harness/' by William Felton, published in London in 1790, we 
are informed that springs were marketed during that time, thus 
showing that this specialized industry had been started. 

Obadiah Elliott, a noted English carriage builder of Lambeth, 
obtained a patent in 1804 for a means of suspending vehicles on 
elliptic springs. The Society of Arts awarded him their gold 
medal and the popularity of his product, and his success in gen- 
eral, were doubtless prompted by this official recognition of merit. 

The mechanics of plate springs were expounded by Clark 
(1855), although the laws governing their deflection were in- 
correctly stated. Later, and in our own day, Reuleaux gave a 
more nearly correct expression for deflection and stress of these 
members. In 1894 G. R. Henderson corrected the Reuleaux 
formula for deflections, while Professor John Perry called atten- 
tion to the internal stresses produced by "nipping." 

Uniform thickness of leaf spring steel is of immense impor- 
tance. Close tolerances in this direction were not to be had when 



materials were hand-made, except at a great expense. The process 
of rolling Steel, first introduced by Cort, overcame many of these 
objections, but even the rolling mill has undergone another change. 

To Wedgwood, the scientific English potter, we are indebted 
tor the Pyrometer. The original instrument has passed through 
many changes and has been superseded by the improved apparatus 
of LeChatelier, Sir William Siemens and others. The later types 
of these instruments, through their increased sensitiveness, have 
made possible increased production, coupled with uniformity. 

Since the late Dr. Charles P. Dudley, of the Pennsylvania 
Railroad, began his first investigation on spring steels, metallurgy 
has been able to give to the world a series of most valuable spring 
steel alloys. Perhaps the greatest strides have been made in the 
selective processes of heat treatments. 

The introduction of the electric furnace for the manufacture 
of steel by Stasassano, Kjellin, Heroult, Girod, and Hiorth, and 
the work on the micro-structure of steels first introduced by Dr. 
Sorby, of Sheffield, and improved upon by Martens, Roberts- 
Austen, Stead. Ewing & Rosenhain, Guillet, Sauveur and others, 
i- just bringing us into a field of improvements whose latent pos- 
sibilities cannot be predicted. 

The most recent innovation has been the introduction of the 
Spring Endurance Testing Machine, probably first suggested by 
the Editor in 1908 and applied in the following year. This ma- 
chine furnishes us with the knowledge of the durability of a 
spring, reproducing in a few hours or days an event otherwise 
occupying many years. 

Numerous detail improvements, both in the leaf springs and 
the machinery used in their manufacture, have been made, but 
.-pace forbids their further mention. 



PART II 

LEAF SPRINGS 



A WORD OF INTRODUCTION 

Automobile builders are often considerably at a loss as to the 
best method of making known their wants to the spring manu- 
facturer. Why should this be so? Is the subject difficult to com- 
prehend, requiring in every case the presence of an expert? A 
well designed and constructed spring is worthy of the efforts of the 
most skilled mechanic and the most competent engineer. New 
problems are constantly appearing, even to those who have made 
springs a life study. But we are now discussing, only the writing 
of a spring specification. By spring specification we mean a com- 
prehensive statement by the car builder of his requirements as 
to spring suspension. Is that an involved matter? We think not, 
once we have looked it over. 

A spring is a flexible body having no one fixed set of dimen- 
sions. It may have various groups or sets of dimensions, one 
differing from the other, according to the work it is doing. To 
design his product well the spring manufacturer must know defi- 
nitely what load the spring is to carry. These two conditions, 
namely, varying dimensions and knowledge of load will, we 
believe, be found accountable for almost every difficulty experi- 
enced in writing spring specifications. 

The following pages have been written with one object: — to 
present such facts as the car builder wishes to have when laying 
out his springs, and to give them in such concise form as will 
enable him to avoid correspondence. Many of the matters con- 
sidered will be found elementary and our more experienced 
friends may therefore find us tiresome. We ask them to bear in 
mind that we are writing for all classes of spring users, the 
novice as well as the veteran, and we believe that before the final 
page is reached even the more experienced will find some items 
of value. 



PART III 
LEAF SPRING DETAILS 



Details 



We will have occasion, very often, to mention 
various spring details. To avoid misinterpretation 
it may be well to examine a few of these and become acquainted 
with the spring maker's names for them. The car builder will 
then also be better able to interpret the test records and other 
spring literature he receives. 

H a lf Figure 1 shows a "half elliptic," or as it is f re- 

Elliptic quently called a "semi-elliptic'' spring. It is the 
Springs basic or elementary unit from which all other types of 
plate springs are built up. When its curvature is uniform from 
end to end, as shown in Figure 1, it is said to have a "true 



<c*o 




I 

Fig. 1 




True 
Sweep 

Double 
Sweep 



Fig. 2 

sweep" shape. When its curvature is reversed, as 
in Figure 2, it is said to have a "double sweep." 
Double sweep springs are used only under heavy 
trucks, practically never in pleasure cars. They may, 
perhaps, possess more graceful lines than a true sweep spring. 
The change in curvature also produces greater friction between 
the leaves than in a true sweep shape, which would be an ad- 
vantage in dampening the oscillations of a car after mounting 
an obstruction in the road. On the other hand, we are inclined 
to believe that these springs will not retain their shape as well as 
a true sweep spring. This, together with the fact that they 



weigh a little more than a true sweep spring of the same length, 
may neutralize any improvements in their riding qualities. The 
question of true sweep versus double sweep is much in dispute 
and will bear close investigation. Let us say, however, that the 
double sweep should be avoided as much as possible. 



Eyes 



Bushings 



In the above figures "a" and "b" are called the 
: 'eyes" of the spring. Considerable wear is apt to 
take place in these during service, due partly to lack of oil and 
difficulty of access, but perhaps in a greater measure to the 
abrasion of grit and dust always so difficult to exclude. To allow 
for wear the eyes should be bushed. Bushings may 
be of phosphor bronze, Tobin bronze or steel, prefer- 
able in the order named. When bronze bushings are used, case 
hardened and ground shackle bolts should be used in combina- 
p . tion with them. Whether bushed or not bushed, it is 

advisable to ream all eyesi to size. 

The eyes in Figures 1 and 2 are "turned up." 
This is the strongest and most logical construction, 
for in it the leaf immediately below the eye is brought 
well toward the end so as to reinforce the eye. It is 
strong also because the thrust of the bolt falls on the 
leaf itself, the eye doing little more than keep the 
bolt in place. Eyes may be "turned down" as in 
Figure 3. It may happen, in planning a spring, that 



Eyes 
Turned 
"Up" or 
"Down" 

Relative 
Strength 
and 
Advan- 
tages 




Fig. 3 



the centers of the eyes fall very nearly on a line drawn horizon- 
tally through the highest point on the top leaf, as in Figure 4. 




Fig. 4 



Fig. 5 
5 



The spring will then have a downward bend at each end, which 
gives it a weak and awkward appearance. In such cases matters 
can be improved by turning the eyes down, the upper leaf then 
having a slight upward curvature, see Figure 5. When eves are 
turned down the next leaf cannot be brought up underneath 
them as a reinforcement. It should also be noted that in this 
construction the thrust of the bolt tends to open up the eye. 
For the reasons just mentioned it is advisable to use this type of 
eye only in springs carrying small loads. Eyes may also be 





Fig. 6 Fig. 7 

made as shown in Figure 6. These are known as 
"Berlin" eyes, and may be turned up or down. Or 
the eye may be forged solid as shown in Figure 7. 
This last construction is expensive, but is excellent 
when properly made. They are called "solid" eyes 
or "forged" eves. 



Berlin 
Eye 

Forged 
Eye 



Master The uppermost, or top leaf, which carries the 

Leaf eyes, is called the "master leaf/' or "main leaf." 

The leaf immediately below is termed the "long 
plate." The lowest leaf is called the "short plate." 
That part of the axle on which the spring rests is 
variously called the "spring seat," "spring perch," 
or "spring chair." The term "spring seat" is also 
applied by the spring maker to that portion of the 
hort plate which rests upon the axle. 

A little thought will make it clear that the length 
of the short plate is a most important matter. Its 
length governs the length, of all the other leaves. It 
influences not only the amount of material which goes 
into the spring, but its entire action and manner of 
carrying any given load. To the car builder it is not an essential 
dimension. To have it a trifle longer or shorter is not a vital 
matter to him; and. as it plays such an important part in the de- 
sign of the spring, it is in all cases left to the spring manufacturer 
for determination. 



Long 
Plate 
Short 
Plate 

Spring 
Seat 



Impor- 
tance of 
Short 
Plate 
Length 



6 



The bolt holding the leaves together is called the 
uenter "center bolt." It can be furnished with square, hex- 
Diameters a £ on ' cone or fil^ster head. Figure 8 shows details 
of a 5/16" center bolt very extensively used. Springs 



To Suit s pr ing 



I I 



A U-j. 

18 Threads per T — *j ""52 



r 



Fig. 8 



If", 2" and 2|" in width, unless having a very large number of 
leaves, are assembled with 5/16" center bolts. 2V and 3" springs 
have §" bolts and 3 J" springs have them 7/16" in diameter. 

The diameter of spring bolts has been tentatively settled by 

the Spring Division, Standards Committee, of the Society of 

_ Automobile Engineers at this writing. The diameter 

_. of the bolt has been given in terms of the spring 

width. The formula proposed by this Committee is 



D = 



W 



but in our estimation better results are sure to be ob- 

4 

5 W 
tained by changing the formula to read D = — r^- where D=the 

diameter of the bolt in inches and W the width of plates in 
inches. The bearing pressures must not be exceeded and ex- 
perience shows that 600 to 800 pounds per square inch projected 
area on bolts of this description are safe. We can then reduce 
this formula in terms of the bearing pressure. This gives us the 
equation : 



D 



Q x .000835 



to D = 



Q x .000625 



W W 

where Q = the load on each spring and W the width of spring. 

Special Instead of having a center bolt, springs may be 

Bead or assembled with a "special bead" at the center, also 
Nib called a "nib." The relative advantages of center 

bolt and nib form an open question. Many arguments are ad- 
vanced for both constructions ; at present the nib is compara- 
tively little used. 



Location . CC ? ter boh may actuall .v be placed at the center 
of Center '" a Sp . rin S ,,r be located forward of to the rear of 
Bolt that point. One reason, among others, for placing the 

center boh forward of the center in front springs is to 
increase the wheel base. This is perfectly proper but should be 
Off-Center resorted . to u,tl1 S^at care, for when the off-center 
Springs dlst *rice « large it becomes difficult to maintain a level 

spring seat, and it gives the spring a bad appearance 




In I' igure 9 we have a 36" spring in which the center holt has been 
Place, 1 forward of the center. The distance from A to the bolt 
will then he 17" and from the holt to B 19". To find the off- 
center distance we merely get the difference between the two 

hall lengths and divide by 2. Or, conversely, if the off-center 
distance IS specified we can find the two partial" lengths by addin- 
>t to the actual half length in one ease and subtracting it therefrom 
in the other. 

Leaf A " leaves of a spring, except the master leaf, are 

Points usual b tapered at each end. The operation of pro- 

Tapering duClllg thls la l ,er is variously called "rolling,-' "draw- 
ing, and "pointing." The ends of the leaf are ac- 
cordingly called -points." Points are shaped in various ways 
the more common of which are shown in Figure 10 The shape 
of points is largely a matter of appearance and taste. The round 
Point ,. the mo.t common, being used on all carbon spring work 
Uva. points are used in truck springs of alloy steel, French 
point- in pleasure car springs of alloy steel. 

In heavy truck springs, to stiffen the spring, the "long plate" 



ma\ 



not he tapered but he cut oft "full thick." 



Long - o.peieo out dc cut oft "full thick." In 

Plate tha< Case the third leaf may he carried to the <w\ 

Full Thick''"" 1 l;i l>cred. the remaining leaves being spaced from 

there on. Figure 11. A modification of tin'. COnstrUC- 

8 




K — Square 

Iv — Special round (oval) 



M— Round 
X— Egg shaped 

Fig. 10 — Points 



O — South American 
slot and bead 




Wrapper 



Fig. 11 Fig. 12 

tion, used to strengthen the eye, is shown in Figure 12. The 

long plate is here wrapped around the eye and is 

known as a "wrapper." 

In service the leaves of a spring tend to move transversely, 

or from side to side. There are a number of ways in 

mement ^j^ t j ley can k e j™t ni p r0 p C r alinement and the 

of Leaves , - J . v . v , m 

lateral motion just mentioned prevented. Ine sim- 



Saw and plest method is to "saw and bead" all the leaves. 
Bead \ small projection or "'head" on the lower leaf work- 




Section at A B 



Fig. l: 



ing in a narrow slot or "saw" in the leaf above, see Figure 13. 
Metal i- removed from one leaf and metal distorted in the other 
when securing the leaves in this way. It can, therefore, hardly 
be recommended as the best practice. 




Ribbing 



P — Special clip with tube H — Clinch clip G — Ribbed spring 

Fig. 14 

Another means of securing the leaves in alinement is to 
"rib" them, see Figure 14. The rib is supposed 
by many to extend the whole length of each leaf, and 
they do in some foreign makes of springs. In reality it is made 
Strength (),1 b" ()t such length as to extend a short distance be- 
Only neath the next leaf. It cannot be denied that a rib 
Apparent improves the appearance of a spring, apparently 
strengthening it. 'Hie actual improvement of strength and riding 
qualities are very -mall, in fact arc negligible. ( hi heavy truck 

10 



Stress springs having a large number of leaves, each rib is 

Changes short, it may not extend much beyond the tapered 
Due to portion of the leaf, and consequently has little effect 
Ribs on the leaf action. When, on the other hand, a rib 

is applied to a spring with but few leaves, its length becomes 
proportionately greater, extending well in toward the center of 
the spring. Its effect then bears close examination, for it is there 
subjected to the stress acting along the entire length of the leaf. 
It is a well-known fact that, all other things being equal, a thin 
leaf can be bent a greater number of times without breaking 
than a thick leaf. A rib, by thowing metal up above the normal 
surface of the leaf, makes that leaf act as though it had been in- 
creased in thickness ; and, as such, that leaf is more liable to break 
than if it had not been ribbed. In technical language, the stress 
in the leaf is increased because the most remote fibre is further 
from the neutral axis. 




A — I,ipped spring 
B— Button head 
C— Berlin head 



D — Closed open head 
E — Open head 



Fig. 15 



One of the best means of preventing lateral motion is to fit 

the end of each leaf with small side projections extending up- 

_ . ward and close to the leaf above. These are called 

"lips," see Figure 15. They have the advantage 

of placing the holding mechanism at the end of the leaf, 

Jl 



where it is most needed. LipS are not welded on, but forged 
Li the from the leaf itself by spreading it- end before point- 
Strongest in S' They are consequently an integral part of it. 

Construe- Moreover, in making them it is not necessary to 
tion remove metal from the center portions of the leaf, 

and thus add a liability to breakage. 

When a car wheel mounts an obstruction in the road the 
spring immediately above it is suddenly deflected. As the spring 
relieves itself the car is thrown upward. And as the spring 
Qijp S forms a more or less rigid connection between the 

Advan- axle and frame the upward movement of the frame 
tages of, in carries the axle and wheels Up with it. As corn- 
Rebound rnonly constructed, a spring is made to resist only 
downward pressure, the whole force of any upward pressure 
falling on the master leaf. The upward motion of the frame 
after rebound therefore tends to bend the master leaf upward. 
To threw the whole rebound pressure upon that leaf only would 
soon result in breaking it. In order that the leaves of the 
spring may resist the rebound as a whole they are bound together 
by "clips," see Figure 14. 

Clips are of two kinds, as shown. Clinch clips 
mci are used only where but a few leaves are to be held 

together, as at the ends of a spring. When the com- 
bined thickness of the leaves to be clamped is large, special clips 
should in all cases be used. They may be fitted with 
p,. a sleeve or tube slipped over the bolt to prevent bind- 

ing or locking the leaves together. Ribbed leaves, 
for obvious reasons, are not usually fitted with clips. 

The front end of rear springs may be used to transmit the 
driving effort from the axle. The master leaf of the spring is 

~,. t-, the only leaf connecting- the axle to the car and will 
Clips Es- , , . & . .. . t . 
sential transmit the entire driving ettort ltselt unless prop- 
When er ty clamped to the shorter leaves by means of clips. 
Driving Unless such master leaves are secured by clips buck- 
Effort 18 ij n o ail( i breakage will surelv result. The sfirina 

» en y l ,i an ,,f (lC (, ircr should therefore always be advised of 
Spring . . rtt' • 

the fact when afxvtng throiii/h the rear springs so 

thai he can make the necessary provisions as to clips and other 

details. 

12 



PART IV 

EXAMINATION OF MATERIALS 



A few remarks as to the kinds of materials used in plate 
springs are here in order. Wrought iron, as we know it, should 
Prot) consist of the element iron in its purity, with no other 

ties of metal added and with the impurities incidental to man- 

Wrought ufacture reduced to a minimum. It is a compara- 
Iron tively soft and plastic metal. It canont be easily 

hardened. ' When bent or distorted considerably from its orig- 
inal form it retains its new shape. No physical treatment or heat 
treatment will alter this latter characteristic materially ; the iron 
still remains an almost inelastic substance. 

Early in the history of metallurgy it was discovered that if 
a small percentage of the element carbon be intimately combined 
with iron, the characteristics of that metal undergo 
w , a remarkable change and improvement. The new 
Iron Con- meta ^ s ^ much like the old in appearance, can now, 
taining a by suitable heat treatment, be hardened. Should a 
Larger piece of it, after such hardening, be bent from its 
Percent- original shape, it will resist the pressure applied and 
age oi sna p | Dac j c i nto t h e original shape. In short, it is no 

longer a plastic material, but an elastic material. We 
see then that, broadly speaking, steel can be regarded as iron 
which has been converted into an elastic material by the addition 
of carbon. 

Steels contain various percentages of carbon, depending on 
the purposes for which they are intended. When used for 
springs approximately one per cent, of carbon has been found 
Pennsyl- best. In the early eighties the Pennsylvania Railroad 
vania R. R. Company made long and costly investigations into the 
* n " merits of the various carbon steels then on the mar- 
tion of ket. These investigations were conducted by their 
Spring chief chemist, the late Dr. Charles P. Dudley. It 
Steels was found that steels having carbon ranging from .95 

13 




FORGING DEPARTMENT 
Number One Mux 



to 1.10%, or practically one per cent., were the most efficient 

Spring" from all points of view. The spring steel specification 

Steel Con- then prepared has since become standard for vehicle 

tains 1% springs also. It is universally recommended in all 

Carbon branches of the spring industry, having withstood the 

hardest service. As a. simple carbon steel it has so far had no 

rival, and may be looked upon as the acme in that 

.Dragon c j ass f material. It is the onlv material used in 
Brand 4t _ D .«, . 

Dragon .Brand springs. 

The advent of the motor car forced springs into a service 
more severe and exacting than any they had been called upon 
Carbon to P er f° rm during the past. The speed and weight 
Steel No °f the new vehicle produced shocks and deflections 
Longer unknown before. There has consequently arisen in 
Adequate recent years a need for a steel even better than the 
carbon stock described above. 

It has been found that a carbon steel can be greatly improved 
by the addition of very small percentages of the heretofore 
less used elements, such as silicon, manganese, chro- 
« °J mium, nickel, vanadium, tungsten, etc. Steels con- 

taining these elements singly or in various combina- 
tions, in addition to carbon, are called "Alloy" steels. 

It is not our purpose here to extol the virtues of any one 
alloy steel. All have their inherent advantages and purposes 
Standards f° r which they are admirably suited, while many un- 
for Spring doubtedly have bad points. New elements and com- 
Steels binations are constantly appearing. In the course 

of time, by the natural processes of selection, the best alloy will 
survive, and, as in the case of the carbon steels, will be looked 
upon as standard. 

It is often supposed that an alloy steel will, in itself, improve 
.„ the riding qualities of a spring. It is imagined, for 

Steels instance, that to replace a poor riding carbon spring 

Do Not by an alloy spring of the same dimensions though- 
Change out would result in a marked betterment of the rid- 
Kiding i n g qualities. This is an error which we most em- 

Vju Hies ph a tically contradict. The new spring will ride 
exactly the same as the old one. It will, however, possess 

15 



Allov one vast ^vantage m that its "lite" will hive been 

Steels remarkably lengthened. The alloy is a hardier ma- 

Increase terial, better able than the plain carbon spring to 
Length resist repeated deflection. Jn everyday language, the 
Ol Llle spring "will last longer." This is the only superior- 

ity which can be claimed for an alloy steel legitimately. The 
increased cost of the better material is returned in greater en- 
durance and greater resistance to fatigue. 

The fact that an alloy spring will ride the same as a carbon 
spring of the same dimensions will be better appreciated by the 
Effect of engineer, when we tell him that all steels have prac- 
Modulusof tically the same modulus of elasticity. Plainly stated. 
Elasticity the relation between any load and its corresponding 
deflection is the same for all spring steels. This relation being 
constant, one spring must ride the same as another if they are 
of the same dimensions throughout. 

In the vehicle spring industry the thickness of the leaf is 

Thickness measure( i by a g au §' e known as Stubbs or Birming- 

of Spring ham gauge. Its value in decimals of an inch is as 

Steel follows: 

Decimal Difference between 

Gauge Equivalent the Gauges 

3/8 375" 035" 

340" 040- 

1 300" 

2 28r ........... 

3 259" 021" 

018" 



.016" 
.025" 



.017' 



4 238" 

5 220"' 

6 203" 

It will be noticed that three-eighths is listed instead of 00 
(.38), as there is little difference between the two thicknesses. 
Three-eighths is the greatest thickness carried in a carbon stock. 
3/8 the (Greater thicknesses than this may be used, but only 
Greatest with the greatest care or the stresses produced may 
Thickness exceed the elastic limit of the material. Consequently. 
the\' are little used and are not carried in stock. It is unfor- 
tunate that the difference between successive gauge numbers are 

It; 



so irregular. They seem to have been determined more by chance 
than according to any fixed law. 

In order to eliminate the disadvantages resulting from irreg- 
ularities of the Stubbs gauge numbers, the Sheldon Axle Com- 
. . pany has inaugurated the practice of having its alloy 

taffes of ste ^ s rolled in thicknesses measured by fractions of 
Inch an inch. The steps between successive thicknesses 

Thick- are then uniform, and, as they differ one from the 

nesses ether by only 1/32", better grading of the leaves 

can be had, resulting in a more uniform and efficient distribution 
of the material in the spring. 



17 



PART V 



PROPER COMPARISONS OF LEAF 

SPRINGS 



How shall we compare one spring with another? What are 
the indexes of excellence to be looked for in this part of a car? 

E First in importance comes comfort and the ease 

Riding of ridin S- J ud £ e b . v this quality first of all. If a 
spring rides poorly it is not fulfilling its mission and 
should be rejected, but we ask you not to reject it before con- 
Car In- sultin g the man who made it. In determining its 
spection dimensions he very often labors in the dark because 
by Spring of incomplete information. He can hardly be ex- 
Constuc- pected to allow beforehand for all those small details 
tors which contribute so materially to a proper suspen- 

sion. Let him see the car, give him every opportunity to inspect, 
to measure, to weigh, to test, and if he then fails to produce good 
riding, go elsewhere for your springs, but not until then. ' 

Second in importance comes the length of life. The spring 

Endurance must last and endure in service as well as ride prop- 
erly. How can we make sure that a spring will have 
a reasonable length of life and that it will resist wear and its 
consequent destruction? 

The leaves of a spring are never stationary when in service. 
Breakage The - V are constantly being bent back and forth, and 
Produced we know, without further explanation, that no bar 
by Re- of metal can withstand indefinitely such repeated 

Bendinff bending ' If sub J ected to such treatment it will finally 
s yield to fatigue and break. 

W hen we bend a bar or plate of metal we stretch some and 
compress others of its fibres, these fibres again resuming their 
Steel is ori g inal length when the bar is released into its free 
Stretched state - A spring when placed in position on a car is 
WhenUn- deflected or pressed down a certain distance depend- 
derLoad ing on the weight of the car. Its height under the 

18 



car is less than its height as manufactured. And when so deflected 
by the weight of the car the fibres of its metal are stretched. 
It is evident that a spring whose fibres are only moderately 
stretched will last longer than a spring whose fibres are pulled 
to an excessive degree. This pull on the fibres of a metal is 
known as the stress existing in them. We are now ready to 
comprehend the significance of a most important fact: the life 
of a spring is measured by the stress existing in its fibres when 
carrying the loaded car. 

There need be no cause for regarding stress as a deep and in- 
volved technical term. Consider it in every-day language as 

a measure of the pull in the metal which tells us how 
*? -p, nar d it is working. In order to compare one stress 
ttlained with another their magnitude is given by stating the 

number of pounds of such pull which acts on one 
square inch of metal. Thus, if we state that a spring is stressed 
to 50,000 pounds, we mean that each square inch of its most 
stretched fibres will be pulled by a force of 50,000 pounds of 
weight. 




Fig. 16 



^L^ 



til 



How can we measure these stresses? What relation exists 
between them and the dimensions of a spring? Figure 16 
shows a bar of steel held in a vise and deflected by a 
weight at its outer end. The fibres above the center 
of the bar will be stretched, and the fibres below the 
center will be compressed. This fact can be made 
more evident by examining a long pencil eraser bent about in the 
fingers. The eraser is subjected to exactly the same action as the 



Measure 
of Fibre 
Stress 



i«.» 




GRINDING DEPARTMENT 
Number One Mux 






steel bar; it is merely a body possessing stretch to such a degree 
as to make itself visible to the naked eye. 

A represents a fibre near the center of the bar ; B is a fibre 
at its surface, an extreme or outer fibre. A little thought will 
Stress is show that for any given amount of bending the fibre 
Measured B is stressed to a far greater extent than the fibre * I ; 
in the whence it follows that, in any bar, the outer fibres are 

Outer the only ones we need examine for stress. They are 

Fihrp^s 

acted upon most severely, the fibres near the cen- 
ter always being acted upon in a smaller degree. Consequently 
it is always understood when a stress is mentioned that it is the 
stress in the outer fibres. 

It will also be seen that if our bar had been thicker, its outer 
or most remote fibres would have been further 'from its center 
Stress anc ^ ^ or ^ e same d e § ree °f bending would therefore 

Varies as have been stressed higher. The relation between 
Thickness thickness and stress is a simple one, namely, that if 
of the the bar had been twice as thick, the deflection re- 

T -P 

maining the same, the stress would have been twice 
as great. In other words : all other things being the same, the 
stress in a bar will vary directly as its thickness. 

If we examine Figure 16 again a second fact becomes evident. 
If w r e had bent down or deflected the outer end of our bar a 
Stress greater distance than C } all its fibres would have been 

Varies as stressed to a greater extent than before. The rela- 
the Deflec- tion between deflection and stress is also a very sim- 
tion pl e one, namely, that if the deflection had been 

doubled the stress would also have been doubled. In other 
words : all other things being the same, the stress in a bar will varv 
directly as its deflection. 

The stress in a bar is also effected by another dimension, its 
length. If we had increased the length of the bar as shown by 
the dotted lines and still deflected it onlv the same 
Varies In- amount < tne stress would have been much smaller 
verselyas than wu " n the shorter bar, because the angle of bend- 
the Square ing at the fixed end would have been far less. The 
of the relation between length and stress is not quite so 

Length simple, but can be given by stating that if the length 

21 



only of the bar had been doubled its stress would have been only 
one- fourth as large. In brief: all other things being the same, the 
stress in a bar will vary inversely a- the square of it- length. 

Thickness, deflection and length are the only factors which 
influence the stress of a spring. The width of the spring and 
the quality of the metal have nothing to do with stress; they 
cannot change it in any way. 

St re-- is purely a geometrical condition which is influenced 

and changed onlv by the linear dimensions of the 
Stress is " 

Measured s P rm S'- To sum up: Stress is dependent: 

Primarily ]m Qn the thickness of the bar. 

by Shape g Q n t]lc amount we deflect its outer end. 

3. On its length. 



Only 



Re i We have already shown that the life of a spring is 

merits De- governed by the stress imposed on its fibres when 

manded carrying the loaded car ; this fact, together with what 

by Long we have just learned regarding stress, will enable us 

T • r> - O CD 

e to appreciate that : 

Proper 1. To maintain "life" we must use thin leaves 

Thickness f or ] ng life and thick leaves are not compatible; 
ea they cannot exist at the same time. 

2. To maintain life we must maintain small deflections. 

Long life and large deflections are not to be looked for at the 

same time. The amount of deflection necessary in a 

r per spring is fixed by its riding qualities, and it is there- 
Deflection . ,1 

fore not our purpose to say here that a spring must 

be made hard riding to keep down its stress. Deflection should 

be the last condition to be changed in a spring if it is found 

that its stress is high. All other dimensions should be so chosen 

that with a given necessary deflection the stresses are kept within 

the proper limits. 

3. To maintain life we must use long springs. 
T crfh Short springs will not survive as well as springs of 

greater length. 

The true art <>f the spring designer steps in just at this point. 
He must he able to so choose the length of the spring and the 

22 



thickness of its leaves that for the given necessary deflection the 
stresses will be such as will permit a reasonable length of life. 

1. To maintain longevity we must see that proper mate- 
rial is employed. This would seem to be axiomatic, 



Proper 
Material 



and in need of no further explanation. There is, 
however, so much to be said as to the manner in 

which one steel differs from another that we are strongly tempted 

to go a little further. 

It is a matter of everyday experience that if we double the 

load upon a spring its deflection will be doubled. In a simple 

spring the deflection varies directly as the load. That 

T?^? n ?. us relation will, however, not hold true indefinitely, for 

Deflection . 1 . . t 1 , /' 

of Serine's wnen a * oa d ls increased beyond a certain point the 

steel is injured. To make this clear examine Figure 
lfeagain and imagine it to be a spring of one leaf. Suppose we 
increase the load on the bar by increments of 50 pounds, releas- 
ing it to its free height after each increase of load. It will be 
found that each additional 50 pounds produces practically the 
same increase in deflection and that each time we release the 
bar we find it to have resumed its original shape. But as we 
keep on adding weight continually, we will notice that our dif- 
ferences in deflection are no longer the same and uniform, but 
that they have suddenly increased, each being larger than that 
preceding. We will also notice that if we now release the load 
the bar no longer has its former shape; it has been permanently 
bent. This point in the experiment, at which the bar is perma- 
Elastic nently bent and at which the deflections begin to in- 
Limit crease in greater proportion than the load is called 

the elastic limit of the material. That limit can best be meas- 
_.,*, ured by stating the stress which exists at the time. 

Materials Each kind and quality of metal has its own elastic 
Have limit. Wrought iron can be stressed to about 25,000 

Different pounds per sfquare inch without injury, struc- 
Elastic tural steel to from 30,000 to 40,000 pounds, carbon- 
Limits spring steel after teeatment to 110,000 pounds. 

If we now examine an alloy steel in the same way we note 
a marked and' truly wonderful increase in the elastic limit. This 



23 



Allov increase in the elastic limit, together with the ac- 

Steels companying ability to resist fatigue, are the essential 

Have characteristics of alloy steels. We can point out a 

Higher certain Silico Manganese steel, made in the electric 
Elastic f llrn ace, which has an elastic limit of 220,000 pounds 

Abilitv to l )er sc ! uare inch. The vast advantage of such a steel 
Resist Fa- can easily be comprehended. A bar of it held in a 
tigue vise could be bent just twice as far without injury as 

a carton steel bar of the same dimensions. This does not mean 
Elect rir that a spring of this alloy will merely last twice as 
Furnace ^ong as a similar carbon spring. The ratio between 
Silico — the two is very much greater than this. For in 
Mangan- addition to having a high elastic limit these steels also 
ese Steel possess remarkable anti- fatigue properties. Instead 
of only doubling the life of the spring by employing alloy steel 
we increase its life many fold. 

5. To maintain life we must see that our material is prop- 
erly tempered, that its heat treatment is correct. We have said 
jj ea + little on this point so far and fear that its import- 

Treatment ance ma ) r therefore not be appreciated. Each kind 
of Spring and grade of steel requires its own particular heat 
Steel treatment to enable it to endure, and anything short 

of that treatment should not be tolerated. The most expensive 
alloy, if improperly treated, is inferior to carbon steel which 
has been so treated as to bring out all its good points. In this 
connection uniformity must be maintained. The temper must 
be correct in all the leaves and the same in one spring as in 
another. 

What relation exists between length of life and weight of 
the spring itself? We have already mentioned that the deflection 
.p , . of a spring from its free height to its height under 

Between tne ' oa( ' ec ' car determines its riding qualities. De- 
Endurance flection having been fixed, we can support the given 
of a Spring load by using a small number of thick leaves or a 
and Its larger number of thin leaves, the riding qualities being 
ei £ practically the same. The spring with thick leaves 

will be comparatively light, the spring with the larger number 
of thin leaves will be the heavier of the two. But we have 

24 



made it evident that thin leaves result in low stress and there- 
fore longer life. This fact leads us to admit that a heavy spring 
with many thin leaves will last longer than a light spring having 
Increased on ^ a ^ ew tmc ^ l eaves - The increased weight goes 
Weight directly into increased life. For the same riding qual- 
Goes Into ities, by reducing the thickness of the leaves, we can 
Life extend the life of a spring indefinitely. We can 

get as much life as we think poper for the service in question. 
The happy mean in weight must be chosen, and here again the 
skill and experience of the designer show itself. 

In laying out a spring the first dimensions to be determined 
are its length and width. They are closely connected one with 
the other. If not properly chosen an efficient suspension is not 
Prober possible. Thus, if a spring is too long it will be heavier 
Spring than nee ded for the required service. If too short 
Lengths ^ w ^l ^ e either stressed too high and its length of 
for Pleas- Hf e thereby shortened materially, or it will be hard 
ure Cars riding, due to having been stiffened to cut down its 
stress. The factors influencing length and its corresponding 
proper width are many, too many to be fully discussed here. 
Instead of going into such a discussion we insert a table giving 
lengths and widths for pleasure car springs which will produce 
proper riding, as well as proper lasting qualities, provided, of 
course, that there is ample clearance. 

The loads are those which the spring will carry when the 
car is loaded with its rated number of passengers. The lengths 
are those which the springs will have when so loaded. 





Front 


Springs 




Load 


on One 


Spring 


Length 


Width 


350 to 


400 Pounds 


33" to 34" 


IV 


400 " 


450 


a 


35" " 36" 


1 3" 
x 4 


450 " 


500 


a 


35" " 36" 


If" 


500 " 


550 


a 


36" " 3rr 


I 3" 
1 4 


600 " 


800 


a 


s;r " 40" 


2" 


800 " 


1,100 


a 


40" " 42" 


91" 
-4 



25 



Rear Semi-Elliptic Springs 

Load on One Spring Length Width 

L50 to 550 Pounds !<'•" to 18" If" 



550 


650 


700 ' 


850 


900 ' 


1 ,000 


1,000 ' 


' 1,350 


1,350 ' 


' 1,550 



19" 


" 50" 


2" 


51" 


" 52" 


o" 


52" 


00 


1" 


5 o " 


» 


1 " 

- 1 


- * a 


" 60" 


1 " 

*> .1 



2i"to2f 



Rear Three-quarter EllipHc Springs 

Length of 
Length of Semi- Scroll (Link 





Load to One Spring Elliptic Element 

150 to 500 Pounds. 15" to 17" 


to Cent 

IS" 


re Bolt) 
to 19" 


Width 

14" 






500 " 


650 




1 < 


49' 


18" 


ii 


19" 


if" 








650 " 


« ] 5 


« 


i:r - 


514/ 


194" 


" 




2" 








7 7 5 


900 


" 


51£" •• 


85" 


OO 1 " 


c . 


23" 


2" 


to 


•-'!" 




900 " 


1,000 


« 


.vn" •• 


.v;y 


23" 


ii 


24" 


2" 


" 


24/ 


1 


,000 " 


1,150 


(< 


53f " 


.-> r 


24" 


« 


25" 


•2" 


" 


H" 


1 


,150 " 


1,250 




04 


544/ 


25" 


" 


254" 


2" 


a 


24/ 


1 


,250 " 


1,350 


" 


544/' " 


^ ^ // 
.)•) 


25i" 


" 


26" 


2" 


1 1 


- 1 


1 


.350 " 


1,450 


" 


- e " >> 
00 


56" 


26" 


" 


264" 


2£" 


a 


24/ 


1 


150 " 


1,550 


« 


56" " 


58" 


264/ 


" 


27" 


2i" 


a 


91" 

* 2 


1 


550 " 


1,650 


" 


58" '• 


60" 


i i 


" 


274" 


Ol" 
^4 




24/ 






Full Elliptic 

Load on One Spring 
500 to 550 Pounds 


Sprin 

Length 
35" 


gS 


Width 

1 3" 

I 4 










600 


" ;oo 

800 

1,000 
1,100 

L,200 
1,300 

1.100 

1,500 
1,600 


ii 

t • 
1 > 




35" 
36" 

.> * // 

39" 

il" 
13" 

M" 
15" 
Hi" 




1 3" 

1 + 

2" 

1" 

- i 
- 1 

1" 

- \ 

w 4 

24" 

Q l " 

v 2 

24" 









26 



Three-quarter Platform Springs 



Load on One 
Side Spring 

500 to 550 Pounds 



600 



" TOO 
900 
1,000 
1,100 
1,200 
1,300 
1,400 
1,500 



Length of 
Side Spring 

4" " A. „ A *J ft 
o to 4v 



-t i 



51 
53 



49" 

53" 



" " 55" 



55 o7 



57" 



57* 



58" 
581" 



Length of 
Cross Spring 

m" 

394" 

394" to 40" 

39J " 40" 

39i" " 40 " 

40" 

40" 

40" 

40" 



Width 
If" 

1.3" 



4 

2i" 

^4 

91" 
-4 

91" 

■^4 

91" 
-4 



to 21" 



27 



PART VI 

ANALYSIS OF A SPRING SPECIFICATION 



We come now to the matter of spring specifications. We 

have already said that our object in writing these lines is to 
Foreword ena ^ e lnc car builder to make known his wants so 
to Writers clearly as to avoid correspondence, or at least to en- 
of Speci- able him to reduce that correspondence to a minimum, 
ficatioris That aim may, perhaps, be fulfilled in two way-. We 
can tell him what facts are wanted, or we can tell him what 
fact- are not wanted. We will tell him in due course what infor- 
mation is needed, but, just at this point, we believe it will be 
best for all concerned to examine a faulty specification and see 
w herein it fails to supply the information required. In so doing 
we hope not to reflect upon the ability of the car builder, for 
we realize perfectly that he is a busy man who cannot be ex- 
pected to go as deeply into our work as we have gone and 
that he has many other parts of the car to consider. 

A car builder orders as follows : 

TEN P.MR FRONT SPRIXOS 36" LOXC, 2" WIDE, 6" HIGH. NUM- 

bek OF ij-wks. seven. For five passenger car weighixg 4300 

POUNDS. 




Fig. r 



In connection, first, with length. Figure 1. represents a 
.spring whose curvature has been purposely exaggerated. The 



28 



full lines show its shape as manufactured, "free" or 
Length of " on the floor/' as it is sometimes termed. The dotted 
a bpring | mes s j low j ts s hape after applying a load. Imagine 
weights of say 50 pounds placed one at each end of 
the spring, equivalent to a load of 100 pounds acting downward 
upon the axle. What happens? As the weights are applied the 
curvature of the spring decreases — it becomes flatter. And as 
it flattens, the eyes move away from each other ; so that the orig- 
inal length of the spring L 1 is increased to L 2 . The amount of 
flattening and increase of length depends on how much load 
we place upon the spring, and we are forced to admit that : a 
spring has no one fixed length. It has various lengths depend- 
ing on the magnitude of the load it carries. We have been told 
to make our spring 36" long. We accordingly ask: Is this to 
be its length as manufactured or when carrying the empty car 
or when the rated passenger and freight load is being carried? 
Each condition of loading has its corresponding spring length. 
If the spring shackles hang properly with cne load they may 
not hang properly with another load. The differences in length 
are small, to be sure, and may not incline a spring shackle un- 
duly one way or the other, but why not have the shackles hang 
correctly with that condition of loading which exists most often 
in service. 

Another fact will be noted in connection with Figure 17. If 
the action of the load be considered for but a mo- 
« o . * ment it w T ill be seen that the eyes are lowered as the 
Is Variable ^ oa< ^ ^ a ^ s u P on them and the original height H 1 de- 
creases to H 2 . We are then forced to admit this second 
fact that: a spring has no one fixed height, but various heights, 
depending on the magnitude of the load it carries. 

We note that our spring is to be 6" high. Is it to be of that 
height when free or when carrying the empty car? Or shall 
it measure 6" when the rated load is being carried in the car? 
Is it not now evident that each load has a length and a height 
Each Va- which corresponds to it? All of which may be boiled 
riation of down into one simple statement, and that is what 
nh we now w ^ sn to impress most of all upon anyone 

the Length wr ^ing a spring specification : a spring length and 
and Height spring height mean little to a spring maker unless he 
of a Spring knows in addition at what load each is to be measured. 

29 




FORGING DEPARTMENT 
Number Two Mill 



When the height of the spring is measured from the spring 
seat to the center line of the eyes (see Figure 1) it is 

Height called the "outside" height. If so measured the above 
spring would have been termed "6" out." When the 

Inside height is measured from the top of the master leaf 

C^enhi k is ° alled the " inside " hei ^ ht or "opening." If 
so measured, the spring would have been "6" open." 

The inside height or opening of a spring should be specified 

only when it is underslnng, that is, secured below the axle. 

Proper When placed over the axle the outside height should 

Way of m all cases be given. We still find designers who 

Specifying insist on giving the opening when a spring is above 

Cambers the axle. They do not seem to realize that in their 

case the distance from spring seat to the center line of the eyes 

is the essential dimension, and that this dimension will vary 

with the thickness of the spring at its center when the opening 

is specified. 

"The spring is to have seven leaves." How has our customer 
arrived at such a decision? If we give him seven comparatively 
Number thick leaves his spring may be too stiff; if, on the 
of Leaves other hand,, we give him seven thin leaves, his spring 
and Their ma y be too soft, or as he may term it, "sloppy." We 
ti T G f+ ma y or we ma y n °t be- able to so choose the thickness 
to the °^ ^ le seven l eaves that they will best fulfill all re- 

Spring quirements. We may as well immediately state that 
Construe- the number of leaves and their individual thicknesses 
tor are questions which should be left entirely to the 

spring builder for solution. 

They are influenced by so many conditions and so many 
factors must be considered in determining them that 
latters ^ j g erl tirely beyond the knowledge of the usual 
the Num- s P rm S buyer to specify them properly. We must, 
ber of f° r instance, consider the type of car and kind of 

Leaves service, the life of the spring, the kind of material 
and Their anc j its heat treatment, the weight to be carried, the 

Thick- distribution of the material of the spring, its appear- 

nesses . 1 • • 1 

ance, its cost and consequently its weight. 

The final term of the specification reading, "The car will weigh 

about 4,300 pounds," brings us to an item in the specification 

31 



Give total whose importance is seldom appreciated. We ask 
Load each that the following be noted most carefully. A spring 
Spring engineer, in order to intelligently design a spring, 
Must must know the total load in pounds which that spring 

uarry - s f() n/rrv j^ et us not question here just why this 

information is necessary. Accept for the present our statement 
that without definite knowledge of load a spring cannot be de- 
signed to ride well or have a reasonable length of life. 

It may be argued by certain of our readers that they have 

obtained springs without going into details as to loads. That is 

probably true, and in that case the springs were spec- 

prings ified in one of two ways. First, by allowing the 
Obtained , : . fe 

bv Rule- s P nn g constructor to assume from his pervious ex- 

of -Thumb perience what the loads would be. His success in that 
Method case was more or less problematical. Or, secondly, 
Sure of t ] le reader rriay have gotten his spring by changing 
ventuai an () | ( j S j )r j n g design, lengthening and shortening, 
widening and narrowing, raising and lowering, add- 
ing a leaf here and removing one there until the final result rode 
well and had a reasonable life, the length of which he left for 
the future to decide. Such can hardly be dignified by the name 
designing. In the end it is sure to lead to trouble. We will 
say nothing as to the cost of such a method. 

We are told that the car weighs about 4,300 pounds. Is this 
the weight with or without passengers? Was this car loaded 

Loads or not l° ac ' e( l ? ^ e ma y De told that there were five 

Must Be passengers in the car when the weight was recorded. 
Definitely We then ask how much of this total weight came 
Known on t h e front end. We may be told that "about" four- 
tenths of the total load is on the front end. Or we may be in- 
formed that the front wheels only were placed on a platform 
scale and showed a weight of 1,800 pounds. That is definite 
information, but still far from complete. Upon reflecting a mo- 
ment it will be -ren that not all of the weight of the front end 
rests on the springs. Wheels, axles, springs and attached parts 
are dead weights, in which we are not interested. Thev are not 
carried on the springs. The dead weight if not specified must 
be estimated by the spring maker as best he can. We accordingly 



ask, "What part of the 1,800 pounds rests on the springs?" We 
Riffht and ma ^ ^ e t0 ^ tnat ^^^ pounds is so placed. Are we 
Left Hand to assume that the right and left sides of the car 
Loads De- weigh the same. In short, and let this be observed 
sirable thoroughly : The spring maker must know the weight 
in pounds on each spring, front and rear, right and left, and 
he asks that these weights be recorded when the rated number 
of passengers or amount of freight is in the car. It will usually 
be sufficient to state the load for the two front springs collec- 
tively and for the two rear springs collectively. In so doing it 
should be determined from an inspection of the design of the 
car that the right side will weigh approximately the same as the 
left side. 



m 



PART VII 

SUGGESTIONS OF METHODS FOR OB- 
TAINING WEIGHT OF THE CAR 



Having dwelt at such a length on the importance of specify- 
ing the exact weights which a spring is to carry, it is to be 
Loads expected that we give some directions as to how this 

from an information can be secured. In doing so we will 
Experi- have to consider whether the car is still on paper or 
mental whether an experimental model has already been 
Model constructed. Matters will be considerably simpli- 

fied if such a model is at hand, and we will accordingly discuss 
this case first. 

Let us assume, then, that the experimental model is ready 

and has a set of springs under it somewhat similar to those 

which will finally be used. How is the weight rest- 

p o r ing on each spring to be found ? Obviously the most 

Load Must rat * ona ' wa - v to § et ^ le m f° rmatl0n wl ^ De to weigh 
BeinPlace tne car - Before this is done care should be taken 
When Get- that it is in full trim and running order. All ac- 
ting Loads cessories and equipment should be in place, radiator 

ana vi- anc j tan j <s filled. And last but bv no means least, 
mensions t , . - J £ . - « , , , 

the rated number ot passengers or freight should be 

in the car when these measurements are taken. 

Drive the car upon a platform scale and record its total 

weight. Back the car ofY so that only the front wheels remain 

_ .« ,011 the scales. This will give the total weight of the 
-brontiiina . , **-, 1 r , , 

iront end. \\ hen only part ot the car is on the scales 

make sure that the car stands level. If tilted to any great degree 

the weights recorded will not be correct. 

Xow run the car across so that only the rear wheels remain 
on the scales. Record the total weight of the rear 
ear n end. See that the front and rear weights just re- 
corded check up with the total weight of the car. 

34 



Run the right front wheel only on the scales. Record its 
weight. The difference between this and the total 

Weight of f ront we i g ht will give the weight of the left front 

Right and , , J? . .„ . , , , r . 

Left Sides wneel - ° r - better still, weigh the left front wheel 

also and see that the weights of the two wheels check 

with the total front weight. 

Do the same for the rear end of the car, getting the weight 
of the right and left sides. Finally, as a matter of record, weigh 
the entire car empty; also weigh the passengers or freight as a 
unit. 

So much for the car as a whole. YVe must still find the 
weight of such parts as do not rest on the springs. 

Weight of Remove the front axles from the car with wheels 
Parts Not an d springs still attached. Weigh all these as a unit. 
Supported If parts are kept in stock it will be more convenient 
by Springs to weigh them individually and record their total 
weight. 

To get the weight of the unsprung parts as just described 
is without doubt a somewhat troublesome proceeding. The labor 
expended will, however, be repaid many fold in knowing that all 
this has been done toward getting the best of spring efficiency. 
We give below the actual figures as recorded in getting the spring 
loads from a recent car. 

Total Weights 

Total weight with five passengers 4,300 pounds 

Total weight front end 1,795 

Weight under left front wheel 875 

A Typical \y e ight under right front wheel (by 

Case in i( 

Detail difference) 920 

Total weight rear end 2,475 

Weight under left rear wheel ; 1,185 

Weight under right rear wheel (by difference) . . 1,290 

Weight car empty 3,465 

Weight of the five passengers 850 

35 



it 



a 



..' 



(t 




STEEL STOCK 

NUMBKR ONK MlI,I, 

This contains stock for this mill only and is but a fraction of the entire 

stock carried 






Unsprung Weights 

Weight of the front axle 71 

Weight of front wheels, tires, springs, etc 176 

Total dead weight front end —71 + 176 2V* 

Weight of rear axle 321 

Weight of rear wheels, tires, springs, etc 206 

Total dead weight, rear end = 321 + 20(> §27 

Weight on Springs 

Weight on left front spring 875 less i of 247 = 751 pounds. 
Weight on right front spring 920 less i of 247 = 796 pounds. 
Weight on left rear spring 1,185 less i of 527 = 921 pounds. 
Weight on right rear spring 1,290 less \ of 52? = 1,026 pounds. 

Before concluding the tests check up the lengths and heights 
of the experimental springs. Run the car upon a smooth and 

level floor, the passengers still on board, and measure 

Check • 

„ . , the height of the frame above the floor, both front 

and an< ^ rear - ^ote difference in level if any. Stretch a 

Lengths fi ne string across the front spring from eye to eye. 
with the Measure the height of this string above the spring 
Assembly seat. Add or subtract from this height whatever 
ffh^a * s rec l mre d to bring the car to the desired front height 
and record this corrected measurement as the height 
to be specified. It should agree with the corresponding height 
on the assembly print of the car. Do the same for the rear of 
the car. 

Measure the center length of the front spring. Xote posi- 
tion of its shackles. From the position of these and 
qi? vi t ' le l en & tn J ust measured, record the length of the 
p ... spring to be specified. It should agree with the length 

already found on the assembly print. 
This is the simplest, most direct and most accurate method of 
getting spring data. It should invariably be worked out before 
Analysis ordering springs in quantities. Send the results so 
of Weights recorded to the spring manufacturer, together with a 
of Great- comment on the riding qualities, and he can ask for 
est Value nothing more. We find many builders on checking 
to All U p sam pi e S p r i n g S< telling us merely to raise or lower 

37 



the springs by given amounts. Such information is acceptable 
and often adequate, but, if at all possible, we earnestly urge that 
an analysis be made such as we have described above. 



Other but 

Indirect 

Methods of 

Obtaining and sllould b e used ° n ly when approximate figures 

Weights are sufficient. 



There are other methods of getting the weight 
on the springs. They are not as direct as the above, 




Fig. 18. 

The first of these methods is as follows: Stretch a string 
from eye to eye of the spring and note carefully the height of 
F' t A thiS strin§ " above the spring seat. Remove the spring 

proximate from the car and place {t u P on a P latform scale 
Method ' e( l ui PP ed wi th a screw jack similar to that shown in 
Figure 18. Record the weight of spring and other 
parts on the scale. Now apply pressure to the spring, deflecting 
il until it again stands at the same height as it did when under 
the car. Record this second weight. The difference between the 

38 



first and second weights will be the weight carried by that par- 
ticular spring. A tensile testing machine may be employed for 
this purpose. But because of the large loads for which it is con- 
structed will hardly be as sensitive as the smaller platform scale 
or as accurate. 

It should be noted that this method does not require that a 
spring be used which w r as designed for the car under investiga- 
tion. Any spring may be used which will fit the car. The spring 
in this case becomes a weighing mechanism and serves the same 
purpose as the helical springs in the familiar spring balances 
used by shopkeepers. 

The only objection that can be made to getting the w T eights 

in this way is the part played by friction, which is apt to vary 

m , _ the results. To show that friction effects the deflec- 

Tne Inac- ... 

curacy tlon °* a s P nn g proceed as follows : Having bal- 

Caused anced the scale with the spring upon it, compress 
byFric- it gradually, turning the screw jack always in the 
tion of downward direction, until the desired height is 
weaves reached. Record the weight. Now compress the 
spring, say 1" beyond the desired height and gradually unscrew 
the jack, turning it always in the upward direction until the de- 
Neutraliz- s ^ rec ' height is again reached. Record the w r eight. It 
ing Fric- w ih be noticed that the two weights are quite dif- 
tion Partly ferent, the "downward" weight being larger than 
by Rap- the "upward" weight. This difference is caused by 
ping friction between the leaves, which retards the 

motion of the spring. The effect of friction can be partly neu- 
tralized by rapping the spring several times with a hammer, both 
when under the car and when under test. 

Should no platform scale of sufficient size to weigh the entire 
car be handy ; approximate spring weights can be had as follows : 
A Second R emove the front axle, the springs remaining on 
Approxi- the car. Roll a small portable scale under the middle 
mate of the car with a small screw jack upon it. On top 

Method f the jack place a wooden beam long enough to span 
the distance between the two spring seats. Raise the jack until 
the car is at the desired height. Record the weight and sub- 
tract from it the weight of jack, beam and springs. 

39 



All these methods suppose that a ear has already been con- 
tructed or at least that a chassis more or less eomplete can be 
weighed and measured. What is to be done when 
the car i- still on paper? In this case approxima- 
tions to the weights on the springs can he had by the 
f< 11< wing method. It will be necessary to know the 
weight of each part of the car and the horizontal 
location of the center of gravity of each part. Such 

information the manufacturers of the various parts should be 

able to furnish. 



Getting 
Loads 
Before a 
Car Has 

Been Con 
structed 




i "r 



FlG. ID 



The method is based on the principle of moments. Con- 
sider /4, Figure 19, as the center of rotation. Each part of the 
car may be considered as tending to rotate the car 

Method of d ownwan j The tendency to rotate will be the mo- 
Balanced r , * A MAI 

Moments mcnt of the part about A as a center, lnat moment 
will be the weight of the part multiplied by its hori- 
zontal distance from A. Thus, if the radiator weighs 100 pounds 
filled and the distance l x is 12", the moment of the radiator will 
be 12x100 or 1,200 inch pounds. In a similar way the mo- 
ments of all the other parts about A may be found. 

The sum of all these will be the total moment tending to 

rotate the car downward about A. Represent it by 2 M, the 

sign 2 standing for "sum." This total downward 

bumma- moment will be resisted by the moments produced 
tion of , . , , . r 

Moments -' front and rear spring loads acting upward. 

Let the load on one front spring be Wf and the load 

on one rear spring be \V r . Also call the distance from A to 

the front axle h and the distance from A to the rear axle l x 

The moment of each front spring load will be Wf /f and the 

40 



moment of each rear spring load will be W r A. We can now 
write the equation : 

2Wf/f +2 W r It = 2 M 

in which Wf and W r are the unknown quantities. All the loads 
should be in pounds and all the distances in inches. 

We also know that the spring loads as a total must equal the 
combined weight of all the suspended parts. Call the total 
weight of these parts T. We can then write : 

2 W f + 2 W r = T. 

A Method We now have two simple simultaneous equations 

Within which can readily be solved for Wf and W r . We 

n^ C ?^ e admit that all this is cumbersome, tedious and re- 
of Modern . ....... 

Engineer c l ulres mor e or l ess engineering knowledge in its so- 

ing De- lution. But we fail to see why it should be beyond the 

partments capacity of any modern engineering department. 



41 



PART VIII 

MODEL SPECIFICATIONS FOR LEAF 

SPRINGS 



We come right clown to the point now, where a specification 
is to be written — where we prepare a statement which is to show 

the spring builder what is required. 
Sugges- 
tions for Before going ahead we are tempted to make a 
the Prepa- few suggestions as to the preparation of drawings 
ration of an( j ^\ ue prints, and we trust that in so doing we will 

-.* ~ not be regarded as over critical. We will make 

tions fe . 

springs no matter in what fashion you send in the 

information, for any and all drawings and prints and sketches are 

welcome. We will digest them all, for we have spent many years 

in tasks just such as these. We offer this advice in the hope 

that it may result in eliminating those small perplexities which 

take up our time and prevent us from getting down immeditaely 

to a proper interpretation of your requirements. 

We ask that the car builder submit us a print showing what 
he requires and in which he may embody such facts as we will 
We Prefer snorl b' as ^ t° r - Note that we ask for a bona-fide 
a Print, blue print. Do not send a pencil drawing. If you 
Not a Pen- do, you will have no fac-simile record of your own 
cil Sketch. i rc fer to. Do not send the tracing itself. Keep it 
so that you may make prints for your own use. And we earn- 
estly ask that you do not make prints from a pencil drawing 
Legibility u P on transparent paper. Such prints are seldom 
of Figures legible. They arc acceptable, to be sure, but is not 
and Di- the work of inking in such a drawing small compared 
mension with the improvement which results. We recall cases 
in which much puzzling and consultation was neces- 
pary before arrow heads could be distinguished, or dimension 
lines followed ii]). or the figures themselves deciphered. 

\-2 



Place the name of your firm on the print. The spring maker 

has hundreds of prints. They pass through many 

irm s hands. If your print should become detached from 

Name on , J f , , „ . 

Prints your letter or order he may not be able to identify it 

without considerable searching and consequent delay. 

Number your prints. If you do, you can much more readily 
refer to them in correspondence. Place some symbol upon the 
Number P rmt so that tne designer may know that he has your 
Your latest edition of it. He has all your prints gathered 

Prints together. If not properly marked he may acciden- 

tally pick up an obsolete issue of the print. A simple method of 
noting revision is to place after the print number a new letter each 
time a change is made upon it. Thus, if the original 

Z SS ^ e issue is 1,296, call the first revision 1.296A, the second 

Letters ' . 

revision 1,296B, etc., etc., changing the issue letter 

every time the print is corrected in any way. Many place a list 

of the revisions upon the print. This is admirable, but does not 

show at a glance that the latest issue is at hand. 

Sraecifica- "^ n P rmt 1^0, we submit model specification for a 

tion for a semi-elliptic spring. Note that the spring is drawn 
Semi- only in outline except that the top leaf is shown. 

Elliptic When checking up a drawing look over the follozmng 
bpring fo S f £ see t j iat no j tems nave been omitted. All di- 
mensions and loads should be stated as they are to be when the 
car is carrying its full rated load. 

Details to Be Included in Specifications: 

Width 1. Width of steel in inches. 

2. Total length center to center of eye, always 
Partial ' measured horizontally. The partial lengths, from eye 
and Total to center bolt, also measured horizontally. State 
which errd is the front end. 

3. Height from the spring seat to center line of eyes. This 

dimension should be given as it is to be when full rated load 

is in the car. If for any reason the height at the 

Height or rated ] oa( j canno t be given, give the height for the 

empty car. In any case give length and height which 

correspond to the given load. This is very important. 



I. If one end of the spring is lower than the other, show 

the difference in height. The difference in height to be measured 

from the lower eve to a line drawn horizontally 

SiLt* 5 through the upper eye, that is: parallel to the spring 

Each End cA . ,. |V ....... „ , _, 

seat. Such a difference in height is called a drop. 

When the eye- arc at different heights do not measure the center 

distances along inclined lines; measure them horizontally just 

as though one eve were at the same height as the 

JLievei other; further, when the eves are at different heights 

Seats , r , , , 1-1 

be careful to keep the spring seat horizontal or 

"level." The spring manufacturer will make it so unless other- 
wise directed. 

5. Show inside diameter of each eye. If they are to be 
bushed show a bushing on the drawing and state of what material 
In c ide ^ * s to ^ e ma< ^ e - ^ ne outside diameter of the bush- 

Diameter m S> however, need not be given. If for good reason 
of Each there is limited room at the ends of the spring show 
Eye the outside diameter of the eye itself. This should 

usually be left to the spring designer for decision, as it is always 
the best policy to have him make it as large and strong as he can. 

(>. Give the load which the spring is to carry when the di- 
mensions are as shown. This should preferably be 

oa on ojven with the rated load in the ear. In any case 
Spring* . . . . . 

state the condition of loading which the given load 

represents ; that is, state whether the given load is based on the 

rated load or includes a stated percentage of overload. 

7. Show location of oil holes if they are de- 
Oil Holes sifed . giye their details 

Spring _ , ,' , 

g ea |. s. dive length of the spring seat. 

\l (jive the amount of clearance. By clearance we mean 
the distance which the suspended part of the car may be lowered 

„, beyond its loaded condition until any two adjacent 

(Jlearanee * 

parts strike each other. When measuring for clear- 
ance be Mire to examine all parts of the car. Mud guards, spring 
brackets and other side parts are just as liable to decrease clear- 
ance as parts underneath the car. 

44 



Front or io. State whether the spring is a front spring or 

Ctassof a rear s P rin &- Give tyP* of car and some indication 
Service °* ^ le c ' ass °^ serv ^ ce m which it is to be used. 

In print 101 is shown a semi-elliptic spring having a "plain 

<< Plain en d" at eacn en d- The on b' additional dimensions 
End" necessary are the center length and overall length. 

Spring They are required in order that the ends may be 
properly shaped and the spring tested under conditions the same 
as those which exist in service. 

In print 102 is shown the cross spring of a platform rear 

suspension. If possible, keep the eyes turned as shown 

orm m ^j s drawing, because such a construction is the 

strongest. We have already referred to this in Part III. 

It is not advisable to specify and buy the cross spring sepa- 
rately from the side springs. Specify the whole platform sus- 
pension at the same time. The actions of the cross 
Orrfpr 
„ . and side springs are so intimately connected that it is 

in Sets not d es i rarj le to design one without knowing the char- 
acteristics of the other. It is only by designing and 
making them at the same time that proper riding qualities and 
low stresses may result. If they are designed independently it 
is very easy to throw upon one or the other more than its proper 
share of the total deflection. The stresses in either the' side or 
cross may therefore become high and reduce its life materially. 
When only When the entire platform suspension is specified 
Cross of a at the same time it will not be necessary to give the 
Platform load carried by the cross spring, its load can always 
Is Ordered ^ t determined from the load on the side springs. 
thp S'rl When the cross is specified by itself and the spring 
Spring's maker knows nothing about the side springs with 
Should which it is to operate the load on the cross spring 
Be Sent should always be specified. 

In print 103 we show T model specification of a three-quarter 
scroll elliptic rear spring. Many of the remarks made in con- 
Three- nection with semi-elliptic springs will apply equally 
Quarter wdl to three-quarter springs. The height of the front 
Scroll eye above the lower spring seat is an important dimen- 
Elliptic s i on . The height of the whole spring should be 

45 



measured from the lower spring seat to the upper spring seat. 
In the spring shown, the spring seat of the quarter spring is un- 
derneath it. The height there given is measured from the inside 
edge of the quarter spring to the outside edge of the 
^,,° semi-elliptic spring, and is therefore called the "in to 

mension ou *" ne *§ nt °* tne spring. In rare cases, when the 
upper spring is fastened below its bracket, and the 
spring seat of that spring is above it, the height of the whole spring 
is measured from the outside edge of the lower spring to the out- 
side edge of the upper spring. This height is called 
uut to t | le .. (mt tQ QUt " height. In all cases the aim should 

rnension ^ e to measure tne height from the face of one spring 
seat to the face of the other. The horizontal distance 
between the two center bolts should in all cases be given, also 
the horizontal distance from the upper bolt to the front end of that 
spring and from this bolt to the links. 

The curved part at the end of the quarter element is called 
the "scroll." The details of this may be left to the spring de- 
signer, but a statement as to what style or size of 
c 1 a scr0 ^ ls preferred is not undesirable. State, for in- 
D ta"k stance, whether it is to be small or large or like a cer- 
tain previous order. In any case do not place an arbi- 
trary scroll on the drawing ; shape it as nearly as possible like that 
which you wish furnished. 

In Part VII many points in connection with three-quarter 
springs are brought up. Look them over carefully before check- 
ing up your drawing. 

Print 104 shows specification of full elliptic spring with 
Full a head at each end. In such springs the inside 

Elliptic height or ''opening" under load usually determines 
the clearance. The opening should, therefore, be determined ap- 
Examine proximately and carefully examined before finally 
Opening sending out designs for this class of springs. It is still 
Carefully advisable, however, to measure the height of the spring 
from spring seat to spring seat. 

Double Print 105 shows specification of double scroll 

Scroll full elliptic spring. Remarks previously made as to 

Full style of scroll and inside height, apply also to this 

Elliptic c i ass f spring. 

46 



PART IX 

CONSIDERATION OF IMPORTANT 

DETAILS 



The fastenings of a spring are in many respects as important 
an item of design as any part of the spring itself. If the fasten- 
ings are poorly designed, or, if when properly de- 
bprmg signed, they are allowed to become loose, spring 
breakage will result. Just why this breakage occurs 
is too lengthy a matter to discuss here. The fact remains that 
if, after taking all precautions to get proper stresses, material, 
_ heat treatment and workmanship, the spring seat is 

ClittS faulty or the box clips are permitted to get loose, 

Cause breakage will inevitably occur. By box clips we mean 

Breakage the clips at the center of the spring which fasten it to 
of the the axle. It is urged, therefore, that great pains be 

bpring taken to get a proper design for the spring seat and 
box clips and to have the latter of ample size. The aim should 
be to have that portion of the spring between the clips so well se- 
cured as to keep it perfectly rigid and inert ; so that it may more 
properly be considered part of the axle than part of the spring 
itself. When but two clips are used see that they are 
Box uiip sufficiently strong. The following is a simple state- 
ment of the minimum diameter allowable for clips in 
pleasure cars : 

Spring If" wide and under V to 9/1 6" diamete-r 

2" wide 9/16" to f" 

21" and 2±" wide f" to J" 

Bear in mind that these are the minimum diameters. Heavy 
springs, especially in trucks, require heavier clips than those 
listed, and should be carefully figured for stress in the clips. No 
general rule can be given at this time, except that they will vary 
from 9/16" to 1-J-", depending on many things. 

Some statement will be here expected as to shape of the 
spring seat. It is evident that the shape of the spring itself 

47 



changes at the center under different conditions of 
bnape oi loading and deflection. It is, consequently, not possi- 
Seat k' e to so shape the seat as to fit the spring under all 

conditions, and it would hardly seem necessary to sug- 
gest that the next best thing would be to make the seat conform to 
that shape of the spring which exists most frequently in service. 

To make the spring fit well to its seat and to allow for small 
irregularities of the surface in contact a thin packing should 
''Pack- ^ e use( ' between seat an d spring. This packing should 
ing"atthe^ e ^ rm an( l so tnm tnat ft will not compress or flatten 
Spring out in service and so loosen up the clips. Two thick- 
Seat nesses of 6 or 8 oz. duck, saturated with white lead, 
lias been found to act well. 

An admirable way to prevent breakage of springs at the cen- 
ter is to use a third clip to strap the spring down directly over 
Strarminff *' ie center b ^- Such a clip would usually consist of 
Spring a stud at each side of the spring, spanned by a cleat 
With a across the center bolt. Where it is not convenient to 
Third use this arrangement, a fair substitute is to use what 

X P may be called a pressure-block under the clips above 





the spring. This block should be of steel, with its lower surface 
Pressure sha P ed to a sli & htl y greater degree of curvature than 
Block to that of tlle u PP er surface of the spring. Its ends 
Hold will tnen n °t touch the spring before tightening the 

Spring at clips. When the clips are tightened they will tend 
Center to straighten out the block, making it conform to 
the shape of the spring and producing pressure over 
the center bolt hole, see Figure 20. 

The whole question of spring fastening has been very well 
summed up by one of our engineers, when he states : "When 
spring fastenings are so well designed that they would hold a 
spring which has been sawed in two through the center bolt hole, 
no breakage will occur between the clips." 

We repeat that the best of fastenings is useless if the clips 
Car are a H° we d to loosen, and strongly urge that car 

Owner builders bring this point to the attention of car own- 
Must Keep ers. Proper mention should be made of it in the in- 
Box Clips struction books and its importance set forth in such 
° manner as to keep it constantly before the man who 

uses the car. He should go over his clips at least every thou- 
sand miles to see that they are tight. 

Spring seats should be carefully inspected to see that they 
are level, transversely. If uniformity cannot be se- 
- . cured in this respect from seats as forged, they should 

Seats ^ e macmne( i- A spring seat which is not level trans- 

versely will produce a torsion or twisting in the 
spring. Such torsion creates an additional stress which is en- 
tirely uncalled for and hastens breakage. 

In some cars the front end of the rear springs is used to 
transmit the driving force from the axle. When so used the 
spring serves two distinct purposes; it is used as a variety of 
beam to support the weight of the car above it and as a column 
w , through which to push the car. As a straight column 

Spring* is stronger than a curved column, it follows that the 
Takes the P art °f a spring which transmits the driving force 
Driving should be kept comparatively straight and flat. No- 
Effort, tice another fact. The master leaf of a spring is 
Keep it t j on j y j ea £ connec tin8r frame to axle ; if that leaf is 
Plat 

not well clamped to the other leaves by rebound clips 

49 



it will transmit the entire driving effort in itself, tend to open 
up the spring by buckling and finally break. We have already 
mentioned this in Part III, in connection with clips. Always ad- 
vise the spring manufacturer of the fact when driving effort is 
to be taken through a spring. 

The scroll portion of a three-quarter spring is in some cases 
made to fit into a place prepared for it in the end of the frame. 

_ _ T . In order to make the scroll element fit into this part 

Do Not . , . , f , . e , , ,; , 

Prescribe ()t frame some builders specify that it shall be 

Thickness made of a certain prescribed thickness at the bolt. 

of the To have the scroll fit the frame nicely is most desir- 

Scroll able. But we respectfully ask that the spring maker 

ement ^ e CO nsulted before designing this part of the frame. 

Make that part of the frame fit the spring rather than make the 

spring fit the frame. Allow the spring designer full play as to 

thickness of scroll so that he may choose such a number and 

thickness of leaves as will produce the best riding and longest life. 

If the thickness is specified he may either have to build up the 

spring with unnecessary material or he may be so restricted as to 

use too little material and thereby obtain high stresses in what 

he does use. In short, "make the shoe fit the foot" rather than 

force the foot to fit the shoe. 

In our model specification for a three-quarter spring it will 

be noted that on the scroll element we ask for a short dimension 

running back from the center bolt. This is the amount 
T ,, of "flat top," or distance along which the scroll is 

to be kept straight, so as to fit into the frame or at- 
tach properly to the spring bracket. When testing a spring the 
spring maker aims to attach the scroll to his testing machine in 
the same manner as it is afterward attached to the car. To do 
so he must know the amount of "flat top." 

A few remarks should be here made as to the 
„ P shape of springs in general, and more especially as to 

the shape as effected by the height of the spring. 
Experience as well as theoretical reasoning shows that a 
spring rides better and looks better if made so that it is compara- 
tively flat under load. Let us see why this should be so. 

How does the shape influence the riding qualities ? In Figure 
551, let the length of the line W represent the weight or load act- 

56 



ing at the end of the spring. By a simple parallelogram of forces 

Low Cam- tne loac * W can be resolve d int ° a force A, acting 
ber Gives along the spring, and a force P, acting perpendicular 
Better to it. The force A acts upon the spring in much the 

Riding same manner as a weight rests upon a column. The 
force P acts upon the spring in much the same way as though 
the spring were a beam fixed into a wall or support at the spring 
seat. We may consider A as a direct thrust from chassis to 
wheels. Suppose, now, that the car mounts an obstruction in the 




road, thus suddenly increasing W . A and P would of course 
increase in proportion. A, acting along the spring, would be 
transmitted directly from wheels to chassis as an impact or 
blow. P, on the other hand, although also increased, would only 
tend to bend the spring. The increase in P would be stored 
up momentarily in the spring as potential energy, to be relieved 
or exhausted gradually by oscillation or bouncing of the car. 
It will evidently be to our interest to keep A as low as pos- 
sible if good riding is to be expected. To keep A small the 
spring should be kept flat, so that all the weight carried acts per- 
pendicular to it. It is easily seen that the greater the height of 
a spring, the greater will be its curvature and the greater will be 
its tendency to act as a column connecting wheel to chassis. 

A moment's reflection will also show that a high spring will 
require a longer master leaf than a low spring of the same 
center length. Not only that leaf, but the short leaf, and conse- 
quently, all the other leaves, require lengthening. All 
of which makes such a spring weigh more and cost 
more than a low spring of the same length. 'It is 
always more economical to raise a car by means of 

51 



High 
Springs 
Weigh 
More 



properly constructed brackets rather than get its height by means 
of a high spring of great curvature. 

A comparison of two springs of the same length and differ- 
ing widely in height will readily show that the low spring has 
the better appearance. 

Before being able to judge of the riding qualities of a spring 
we must know what relation exists between any load we place 
upon it and the deflection produced by that load. This relation 

is expressed by the ratio of load to deflection, which 
P t vf" ls known as the "pounds per inch" of the spring. It 
Stiffness ma - v we ^ ^ e ca " ec ' ** s "stiffness," as the value of the 

ratio increases as the spring becomes stiffer. Thus, 
if a spring loses 2" in height under a load of 600 pounds, its 
"pounds per inch" or "stiffness" will be 600 divided by 2, or 300. 

We have already seen, in Part VI, that a spring increases in 
length as a load is applied. And as a long spring is less stiff 
than a short spring it follows that the "pounds per inch" of a 
spring will not be absolutely uniform, under all deflections. The 
same spring will show a greater stiffness when tested with 2" 
deflection than if tested under a deflection of 4". The difference 
between any two such readings is, however, so small as to be 
neglected in practice. 

Relation Knowing the stiffness of a spring, we can readily 
Between determine how high it will stand under various loads. 
the Va- Thus: a spring is to carry 800 pounds, shows a stiff- 
nous ness Q £ £oo pounds per inch and is 6" high on the 
Obtained ^ oor - H° w high will it stand when loaded? The 
from the trav el of the spring will be 800 divided by 400, or 2"; 
"Pounds it will go down 2" under the load. Subtracting 2 from 
Per Inch" 6 we have 4" as the loaded height. 



Or, conversely: A spring is to stand 5" high with a load of 
900 pounds and shows a stiffness of 300 pounds per inch. How 
high should it be when free? Its travel will be 900 divided by 
300, or 3", and it^ height free will have to be .V plus 3", or S". 

On the European continent the relation between load and de- 
flection i- stated by noting how many inches a spring will de- 



Flexibil- ^ ect ^ or eac ' 1 - 100 pounds of load. This ratio of de- 
ity or De- flection divided by load, is the inverse or reciprocal 
flection of the stiffness and is known as the "flexibility" of 
Per Unit the spring. Thus, if a spring deflects 2" with 800 
Load pounds its flexibility will be 2 divided by 8, or .250" 

per 100 pounds. To find its stiffness we need only get the recip- 
rocal of the flexibility and multiply it by 100. Thus, 1/.25 x 100 
= 400 pounds per inch. Note that the flexibility multiplied by 
the load, expressed in hundred pound units, gives the deflection 
of the spring. 

A word again in connection with writing specifications. 

. „ . fi We find now and then that a builder will state the 

cation ^ oa< ^ on eac ^ s P rm S when the car is empty and then 

Which S lye the number of passengers. Such information is 
Cannot Be not sufficient. The load of the passengers may be 
Inter- distributed between the front and rear springs in 

pre a various ways and the spring builder is, therefore, 
still in the dark unless he is told how much passenger load comes 
on each spring. 

Other builders will give the free height of the spring together 

_, with its stiffness in pounds per inch. Theoretically 

Heiffht sucn m f° rma ti° n is sufficient, as it should be possible 

Together hy means of it to duplicate a spring. Practically, we 

With would advise giving, in addition, the load and the 

Stiffness, height at which the load is to be carried. This latter 

JNotbui- test j g more positive. The free height can then vary 

TI f*l PTl T 

slightly with no harmful results to the hanging of the 
car; it being the spring maker's aim to carry the given load at 
the proper point. 

A few builders are giving an arbitrary test load which is dif- 
ferent from the actual load carried, the actual load in service not 
Arbitrary being known. Such information is sufficient to make 
Test Loads a spring carry the car at the same height as some 
Should sample previously tried out. Yet the practice cannot 
Not Be b e recommended, being open to two serious objec- 

Sl Ve3 V tions. The first of these is the fact that the spring 
ineyCrive . . 

No Indica- maker cannot judge as to zvhether the spring will ride 

53 



tion of well. He judges riding qualities by the deflection of 

Riding the spring under the actual weight of the loaded car, 
Qualities an d as in this case he does not know the weight car- 
ried in service, he .does not know the deflection in service. The 
riding qualities are consequently in the hands of the builder writing 
the specifications. 

The second objection lies in the fact that the information 
does not permit the spring maker to calculate the stresses which 
. ,. exist in the spring, and he, therefore, does not know 

TestLoads "^^ lctncr tne spring will stand up in service. Stress 
Do Not 1H calculated from deflection, deflection is measured 
Permit by the load carried. As the load carried is not known 
Knowing jt follows that the stresses are also not known. After 
b tress considering the tw r o objections just given we believe 

it will be appreciated that it is always more desirable to make' 
the test load identical with the load actually carried in service. 

The importance of having a sufficient amount of clearance 

should always be borne in mind. If clearance is small the frame 

Insuffi- w *^ strike the axles. To overcome striking, the 

cient spring must, in such cases, be made stiffen Such 

clearance stiffening makes the car ride "harder" and naturally 

and Its increases the weight and cost of the spring. Lack of 

clearance, therefore, forces the builder to use a spring 

of inferior riding qualities at an increase in price. Clearance 

may very easily be cut down by improper use of rubber bumpers. 

Bumpers are perfectly legitimate, their function being 

to stop such excessive deflections as would injure the 

springs, but aside from such use they should be placed with 

the greatest care. They can so readily defeat the best efforts of 

the designer of the suspension. 

We repeat that the amount of clearance is a very useful item 
of information to the spring designer. It should be stated as the 
amount which the body can travel beyond its loaded height. 



54 



PART X 



Sheldon Axle Company's Spring Test and 

Data Sheets 



Their Interpretation and Use. 

Under this heading we give a few typical test sheets, issued 
by the Spring Engineering Department to consumers at the time 
of shipment of new samples, or when revising springs. 

The test data sheets are a complete summarized statement, 
analysis, and report of the spring. When once an interpreta- 
tion of these sheets has been made and understood, they will be 
found of extreme value to engineering departments in specifying 
future requirements, or keeping record of changes. 

When sample springs have been tried out and found sat- 
isfactory, the test sheet offers a ready method of specifying dupli- 
cate orders, in a manner that is at once sure and precise : — thus, 
simply give date of test sheet and Sheldon Order Number, which 
appears at the very top of sheet. If any slight changes are desired 
it is only necessary to specify the required changes, for instance, 
height reduction, increase length, etc., and give the number of 
the test sheet to which the indicated changes apply. 

Test data sheets are issued after each revision, change, or 
modification of a customer's springs, hence they form a compre- 
hensive chronological record of all changes, as well as an engi- 
neer's and manufacturer's specification. 

Attention is here directed to the fact that in giving details on 
these sheets a certain fixed order of statement is always followed. 
Thus : first, the material of which the springs are made is given, 
after which the following sequence is observed: width of steel, 
number of plates, length at the customer's specified camber, free 
height, size and location of center bolt or bead, grading of steel, 
size and character of eyes, style and shape of spring. At this 
point other details are accounted for which are not constant for 
all springs ; these are : the method of alignment, type and number 
and location of rebound clips, length of short plate, off-center dis- 
tance (eccentration) of center-bolt hole, drop; also, in springs 
composed of more than one element, the length of links and length 

55 



of flat top as in three-quarter elliptic scroll springs, and then 
follows additional description peculiar to the given spring. Next 
in order of statement is specified the load for which the spring 
has been designed (there are some few exceptions), and the 
height which the spring shows under this load, and last is given 
the stiffness of the spring. 

Specification No. 1 

(Semi-Elliptic.) 

Smith Auto Company ; Washington, Mo. 
Smith Order No. 1234, 4/30/12. 
Sheldon Order No. 23456. 

Model K, 5 Passenger Tourer, E. S. M. 

Front. 

2 i" x ; x 40" at 3f" out x 5f" out. 

5/16" CB 2" off center, 

P/32-— 9/32 i I , 7/3a_7/3g—7/32 steel, 

9/16" B. B., true sweep, clip 3rd spec. & tube, slot & bead. 

Short plate 16", 13/18" off center, 1" drop long end. 

Tests at 3§" out 730 lbs. 315 lbs. per inch. 

Explanation of Terms: 

2]" — the width in inches. 

] — the number of plates. 

40" at 3f" out — the length in inches center to center of eyes, when 

the spring has a camber of 3 J" outside measurement. 
5 J" out — the free height outside measurement, see Figure 1. 
5/16" Cli 2" off center — indicates that the plates are held together 

by a 5/16" center bolt which is 2" off center, making the 

distance from one eve to center bolt IS" and from the other 

eve to center bolt 22". 

9/32— 9/32— ] — 1— T/32— 7/32— 7/32— the thickness or grading 
of the plates from main plate to short plate. 

9/16" P>. B. — meaning that the eve is lined with a bronze bush to 
take a 9/ 16" bolt. 

56 



True sweep or T. S. — the shape and style of the spring. The 
initials "T. S." not only give the shape of the spring, but in 
this case are synonymous with "semi-elliptic spring." If 
this spring had had a double sweep shape, D. S. would have 
appeared at this point. 

Clip 3rd spec. & tube. — shows that on the 3rd plate (the main 
plate being number one) a special or bolted rebound clip 
has been placed, and that it is equipped with a tube or spacer 
slipped over the bolt. This clip naturally holds together the 
main plate, long plate and 3rd plate. 

Slot & Bead — the method of alignment. 

Short plate 16", 13/16" off center — the length of short plate 
and the amount it is eccentrated. 

1" drop L. E. — indicates that the eye on the long end is 1" lower 
than the eye on the short end, when the spring seat is hori- 
zontal. 

Test at 3f" out 730 lbs. — is the load which the spring supports 
when compressed to 3f" outside measurement; this is the 
load and height at which the spring has been tested. 

315 lbs. per 1" — the stiffness of the spring, it is the average load 
required to deflect the spring 1". 
The letters E. S. M. indicate that the above springs were 

manufactured from Sheldon Electric Silico Manganese Steel 

Specification No. 2 

(Three-Quarter Scroll Elliptic.) 
Smith Auto Company ; Washington, Mo. 
Smith Order No. 357, 5/7/12 
Sheldon Order No. 25431. 

Model J, 7 Passenger Tourer, E. S. M. 

Rear. 
2V x 5/7 x 55" at 9f" in to out x 7f" out Bot., 11±" out Top. 
5/16" CB 3i" off center, 

11/32— 5/16— 5/16— 5/16— 5/16— 9/32— J Steel Bot. 
|_5/16— 5/16— 5/16— I steel top. V Bush R. E., §" Bush 
F. E. L. E., clip 3rd Rear & tube, 2nd and 4th F. E. and tube, 

57 



Slot and Bead bottom, saw. and bead top, 2" links, 6" flat top, 
length scroll 19" plus :V\ travel scroll 1£", travel bottom 3f". 

Test at 94" in to out 985 lbs., 200 lbs. per 1". 

Explanation of Terms: 

'!\" — Width of spring. 

5 3 — Indicates that this is a spring composed of two elements, 
the upper portion having 5 and the lower 7 leaves. 

55" at 9f" in to out — the length of the spring measured on the 
bottom half, when the combined spring stands at 9}" in to out 
i see page 46.) 

^ I" out Hot. — the free height of the bottom or lower half, outside 
measurement. 

11 |" out Top — the free height of the top or upper half; in this 
case the scroll portion, also measured outside. 
(See Figure 1 for method of measuring, also the Glossary.) 

5/16" CB 3V off center — the size and location of the center bolt 
in the lower half, as explained in Spec. Xo. 1. The size of 
the center bolt in the upper half is not given separately, unless 
it differs from the bolt in the lower half. The position of 
the center bolt in the upper half is indicated farther on in the 
test sheet, where it states "length of scroll 19" plus 3"", mean- 
ing that the distance from a perpendicular passed through the 
center of the scroll eye to the upper center bolt, is 19" and 
from that center bolt to the front, or plain, end of the upper 
half is 3". 

!1 32-5/16-5/16 etc. Bot. ) -the thickness or grading of the 

- „, tH V steel, bottom and top respec- 

| — 1/16 etc. top. I • i 

1 ) tively. 

\" bush K. E. — the size of bolt for which the eye is bushed, both 

top and bottom, at the rear or scroll end. 
•':" bush F. E. L. E. — indicates that the front eye of the lower half 

is bushed for a "'" bolt. L. E. shows that this is also the 

long end of the spring. 
Clip 3rd Rear & tube — shows that a bolted rebound clip equipped 

with a tube or spacer has been attached to the 3rd plate, top 

and bottom, at the rear end. 



2nd & 4th F. E. & tube — shows the number, kind and position 
of rebound clips attached to the front end of the lower half. 

Slot & Bead bottom — The method of alignment used on the lower 
element. 

Saw & Bead top — the method of alignment on the upper ele- 
ment. (See page 10 for description.) 

2" links — naturally means that the two elements have been as- 
sembled with 2" links. 

6" flat top — the distance from the clamped, or front, end of the 
upper half along w T hich it is kept flat to form the seat. This 
element is then curved or arched from the flat portion to the 
scroll. 

Length scroll 19" plus 3" — has been explained above under the 
topic "5/16 CB etc." 

Travel scroll If" I — the deflection of the upper and lower 
Travel bottom 3J" j elements respectively, under the test load 
of 985 lbs., when the spring is properly assembled. 

Test at 9§" in to out 985 lbs. — The load and height at which the 
assembled spring is tested. 

200 lbs. per 1" — The stiffness of the combined spring. The expla- 
nation given in Specification Xo. 1 on the subject of test and 
stiffness applies to the above as well. 

Specification No. 3 

(Full Scroll Elliptic.) 

Smith Auto Company ; Washington, Mo. 
Smith Order Xo. 1425, 5/12/12, 
Sheldon Order Xo. 19877. 

Model F, 5 Passenger Speedster, Dragon. 

Rear. 

If" x 6 x 38" at 10*' ' out x 8" out Top,, 6i" out Bot. x 5/16 CB. 
1-2-8-2-3-3— J" bush., Full scroll, lip 4, Clip 3rd, If links, S. P. 16". 
Test at 10r out TOO lbs. 175 lbs. per 1". 

59 



Explanation of Terms. 

If— Width of spring, 

6 — Number of plates. The number of plates top and bottom is 
the same on full elliptic springs ; therefore one figure gives 
the number top and bottom. Compare this with Specifica- 
tion No. 2. 

38" at 1(H" out — the length of the spring measured from center to 
center of eyes on the lower half, when the spring stands at 
10V' outside measurement. In exceptional cases only, the 
upper half is slightly longer than the lower. 

8" out Top 6^" out Bot. — free height of the upper and lower ele- 
ments respectively. 

1-2-2-2-3-3 — The thickness or grading of the steel. This is the 
same in both elements. 

Full scroll — Type of spring. (See Model Specifications, Drawing 
Number 105.) 

Lip 4 — Method of alignment. In this case four plates are lipped 

top and bottom. 
Clip 3rd — shows that each end of each element is equipped with 

a rebound clip on its third leaf. As the words "special" and 

"tube" are omitted, this is a regular, or clinch, clip. 
If" links — See Specification No. 2. This being a full scroll spring, 

links are used at both ends. 

The explanation covering the balance of this specification is 
the same as in Specifications 1 and 2. 



CO 




VjMEN CftRH~<\t*G loRO Of 130 V-BS. 



730 \_a* \s> "The Voro 0»* Out Sp«\ng, V/wen 
Crs \» Crw«xm4g HxTto ViuMBtR Or VMbtwtns. 



CV-E*W&NCE. A \fJ«EN \_OftOEO 



SMITH FWJTO CO. 

V/RS«\N&TON, \AO. 

FRONT 5?R\NC V\00e\_'H' 
5 PRS5. TOURtR 

Qws- No. \00 





























= ~- 








£ ,. 


-V 












V= 


^^^^r^^^ ^^^ 


^^^ 




~T 


1 






^^ r««T t m *& 


Spkvnc, To Hbue. Thc Gww Un&ths ftno V\t\GWT 
*WHtN Cftwv<m<i \_QftQ Or SZ50 \_e6. 








Truck \s. CwRy^G \ts ^ftTto Votva. 




SM\TH RVJTO CO. 

VHSHmSTON, MO. 

REftR SPR\NC. MOOt\_*M* 
5T0U TRUCK. 

SCPA-t i= \ Wft Vfc-\"Ut 
Dwg No. \0A 







v> th_3,; f . 




■>C<^^—^ 






5k" 


mr^^^^^ 


^ 1 






|) 


n 


ft 


To OPtRRT^. \l* C.O»WtCT\ON V/\T« RtRS &\Ut 55>Rl~S 

Sbown Ox Owrvmng Ho. \\5 

SPUmo To \A5WC T«t iMtN \_tV»GTWB ftxo Y\E\&HTt, 

Cv.EV\^ ?>H»CKVtS <o" C. To C. To Sit \NO-ooto 






SM\TVA [\0T0 00 
CftOSS SPrl\U(i \A0VJt\."0" 

^ TON TRUCK 
Dwg No. \02 











-* 




H-~H 




/ 


1 J 






1-^-1 " 


h 


1 | 








* i 






LJ 




1 




SE 







Svfn~a To Hrs/c T„t Gmw Unaim *• 
Whin Cmir^ng Low Of ^6.5 \-a&. 
^&5 \-M \sT«c \-oms On Out 5prv 



PR6atNGW5. 



SVWTVA RViTO CO. 

RERR SPRMG V\0OtV_ "3" 

7 PR5S. TOURER 

scrle * - \ okte vi-mt 





VJ\oth vV 
























^1 
























Spwng To Hrve The Gwin \.chgths ^uo H^aghts 

VIhen Crwryvng \_oro Or \075 \_B5. 

\075 Ve& \s The. Uro On One Spr\ng When 

CM* \* CrRRx\ng Rptteo \_ofto. 

Clerrrnce 7" When Uoroeo. 

Cups Rs. Requvred. 
Sheldon t.S.M. Stcev.. 






SMYTH PAYTO CO. 

\_\GHT OVLUVtRV WI\&OV> 

SCPAXa = 1'' OPTt S-fc-V°i\2. 

Owg No. VOA 



V/*OTH \l 










t m 


















nJ"Ty 

On. Cup ftot-re 

X'-itTnREHo 




















To Mrvi. T 


\-o».o Or TOO \_BS. 

b \a Twt Lofto On 0*iC 
miwo Tlmco Hun\6c« 

t MHCN \-ORDtD 7l 

Rtoumto 










vps Rs, 


Of PftSStNGtHS 
STtt\-. 




SNUTYA AUTO CO 

WASWNG.TON, V\0. 

SPEtOSTtR 
%CR\-t * • i" ORTE. 5-\&-Wt 
Qw& No. \0S 



"The Philosopher may be delighted with the extent of his views, the 
Artificer with the readiness of his hands, but let the one remember' that 
without mechanical performance, refined speculation is an empty dream, 
and the other, that without theoretical reasoning, dexterity is little more 
than brute instinct." — S. Johnson. 



PART XI 



The Sheldon Axle Co.'s Spring Plants and 

Organization 

A narration of the rise and growth of an indigenous indus- 
try — especially if such a one be the most extensive of its kind 
in existence — may be profitable reading, but greater interest 
would be found in a personal visit to such a place. 

We regret that every reader of the preceding pages cannot 
enjoy the privilege of a visit to the Sheldon Axle Company's 
Spring Plants — for it is indeed a privilege — so that to these we 
must bring home, through mere word description, that which 
they will miss. Our other reason for such a description being 
that the knowledge in this form may be more frequently avail- 
able and to a greater number. 

It is just over a quarter century ago that the men who founded 
the Sheldon Axle Company, selected the present site and began 
operations. Their intrepid belief in the undertaking is amply at- 
tested by the results obtained. The present management has 
been directing its policies during the past twelve years, and it is 
due to their precepts and ideals that the most intensive growth 
has taken place. Historically, this is. perhaps, as much as may 
interest the reader. 

The management of the spring plants is in the hands of two 
groups of men ; the one whose aims are production and handling 
of men and materials, and synchronizing one with the other; the 
second class is the engineering organization, whose work is to 
improve materials, methods, and to set the results of engineer- 
ing investigation as the ideal to be approached by the mill. In 
few industries are the engineering and production heads in such 
close contact as here. Practice and theory have been made to 
coalesce to the advantage of both. 

01 



Our description of the plants and equipment may, at times, 
appear inadequate, and may be criticized accordingly ; this is not 
due to a willingness to evade description or processes, but rather 
to the regard we have for the reader, whom we do not wish to 
tire by statements of small detail. 

The Sheldon Axle Company's spring plants are situated in 
the city of Wilkes-Barre, in the State of Pennsylvania, occupy- 
ing a total of fourteen acres, comprising manufacturing, ex- 
perimental, shipping, office, testing laboratories and power build- 
ings. The combined daily production of these plants is over three 
thousand springs, varying in weight from twelve pounds to three 
hundred pounds each. It requires from sixty to seventy-five tons 
of steel to furnish the raw material for a day's work of these 
plants. The transporting of such amounts of materials must needs 
be of a carefully planned arrangement, properly executed and 
working with dispatch and ease. An inspection of the half tone, 
showing a panoramic view of the plants, enables one to appreciate 
the above statement. The number of men employed is over twelve 
hundred. The best makers and largest producers of automobiles 
in this country receive their allotments from this source each 
working day in the year. 

Raw materials, both steel and fuel, are near at hand. There 
never has been a delay for want of either. Ample storage 
room insures against delinquency or miscalculation in this re- 
spect. The steel pits carrying the rolled bar stock contain 
over four million pounds, representing over one hundred and 
fifty sizes of spring widths and thicknesses. The handling of 
heavy materials, such as steel, naturally requires special appli- 
ances. Two overhead cranes take the raw material from the 
freight cars, deposit it in the pits, from where it is further dis- 
tributed to each operator by the same means. 

In a plate spring each plate is a unit requiring, perhaps, dif- 
ferent material, or a different process for its manufacture. A 
survey of the operations required in making a spring will give a 
better idea of the various stages needed to complete the whole 
element. Let us follow the receipt of your order. 

The Filing Department receives, dates, indexes and passes 
it on to the Manager of the Spring Department. You are in- 
formed, at this stage, of its receipt. The Engineering Depart- 

62 



merit, beginning with the Designing Engineer, calculate the 
various elements needed to make up the product. A copy of 
the design sheet is given to the Order Department, who make 
up the Mill Sheets, and these are passed to the Production De- 
partment. 

Owing to the intricate nature of the processes in the Pro- 
duction Department, only a brief description can be given by 
elimination of those that seem of lesser importance. 

The first step in the production is the shearing or cutting 
of the individual plates to predetermined lengths set by the De- 
signing Engineers. From this stage the sheared plates go to the 
Forging Department, where a manifold number of operations 
begin to change the otherwise simple shapes. Here we have the 
punching, slotting, beading and sawing; also the tapering, point- 
ing, swedging, trimming and eye bending. Each operation is 
performed by a special machine, and after each operation the 
plate is gauged and inspected. The half tones herewith give some 
idea of the multiplicity of operations and machines needed to pro- 
duce these results. There is no guess work in any of these pro- 
cesses, nor in those following, they having all been predetermined 
by the Engineering Department; indeed, this is true of all the 
Sheldon Axle Company's Mill processes. 

The next step brings the plates to the Fitter's Bench. Here 
the plates are given their proper shape and set, and receive the first 
of the many processes that are called by the general term of 
heat treatment. This is the critical stage and a very serious one. 
Recording and indicating pyrometers, together with a complete 
semaphore system for indicating temperature, are used through- 
out the production departments. An inspecting engineer at- 
tached to the engineers' staff of the Metallurgical and Chemical 
Department continually watches the process during heat treat- 
ment. At this stage approximate tests are made for load carry- 
ing capacity and shape and reported to the Designing Depart- 
ment. 

Next follow tempering and annealing processes, and tough- 
ness tests of the finished spring. A battery of endurance testing 
machines test springs to destruction. This test is relied upon 
to give the most definite answers to the question of the efficacy of 
all the processes of making the spring. When these steps are all 

63 



completed, the spring is ground, finished, assembled, marked, and 
given a final test, then transferred to the Shipping Department. 
One point has so far been omitted in the description of the 
plants and organization. We feel that this should be stated 
in this closing paragraph. One factor is common to all de- 
partments, for which reason Sheldon springs have become 
famous. The aesthetic element, so often criticised as being absent 
in our American merchandise, must pervade in the finished goods. 
The artistic feature must be made a living issue of each spring. 
It is not considered "good enough,'' though all tests have been 
passed— it must possess distinction — it must bear all the hand- 
marks of the masters of spring making. 



64 



PART XII 

Glossary of Terms 

used in the 

Automobile Leaf Spring Industry 



Alinement- Alignment. The means of keeping the leaves of a 
spring from moving transversely. This is accomplished 
in one of several ways, notably, by use of lips on side of 
each plate, by ribs, slot and bead, saw and bead and partly 
by rebound clips or beetle rivets. The last method is not 
common. 

Alloy Steel. Any steel which owes its properties chiefly to the 
presence of an element, or several elements, other than 
carbon. 

Amplitude. The arc traversed by an oscillating body. 

Anneal. Heating a piece of steel to a low red heat and cooling 
it slowly. This reheating also relieves stresses in the metal, 
and breaks up the coarse structure and brittleness. 

Anti-fatigue. A term applied to a material, as steel, which will 
withstand a large number of applications of load without 
destruction. Such steel is said to possess great Dynamic 
Resistance. The term is comparative. 

Applied Load. The application of a load, continuously, or in 
steps, but without releasing of such load at any time dur- 
ing the test; dimensions measured under these conditions 
are known as "applied load test" dimensions. 

Arch. A distance measured on a semi-elliptic spring from a 
line drawn through the center of the spring eyes to the top 
of the master leaf, or to the bottom of the short plate. 
The height of the arc from the chord. The term Set has 
been used in an analogous way to indicate the distance 
measured to the Top of the master leaf. This term (Set) 
is now used, however, to express a distance measured be- 

65 



tween successive plates of a spring when they are free and 
not bolted or clamped, but with their points just contacting- 
each neighboring plate. 

Synonyms — Camber, compass, height, opening, in dimen- 
sion, out dimension. 

The Opening of a spring and the In Dimension refer to 
the height of a semi-elliptic, measured from a line drawn 
through the spring eyes to the top of the master leaf. 
The Out Dimension is the height measured from a line 
passing through the center of spring eyes to the outside 
of the short plate on the spring. 

Auxiliary Spring. A separate spring, although sometimes com- 
bined with the regular spring, and so disposed as to come 
into action automatically when a certain predetermined 
load has caused the main springs to deflect. The auxil- 
iary springs may be either of the plate, or coil type. They 
may also be composed of a single leaf, a plurality of 
leaves or, more commonly, of a semi-elliptic spring hav- 
ing plain ends ; they are frequently used on heavy vehicles. 
When such springs are used to prevent large deflections 
of the main springs of heavy vehicles, they are called 
Bumper Springs. 

Synonyms — Buffer springs, jack springs, helper springs, 
check springs, overload springs, supplementary springs. 
The last term has recently come into use, being more fre- 
quently applied to a coil or spiral spring designed to act 
with and increase the deflection of the total suspension. 
Back. The main plate or longest plate of a spring, which most 
frequently has its ends turned over on itself, making the 
eyes. 

Synonyms — Master leaf, main plate. 

Band. A ribbon of steel, usually from §" to V thick, formed 
into a hollow box section, having the ends welded. It is 
shrunk on the spring to keep the plates together and 
forms a flat seat for the spring; only used on very heavy 
springs. The portion of the band which rests on the 
spring seat is called the Butt, or Head of the band, while 
the upper is called the Strap of the band. 

66 



Barrel-Shackle or (Shackel). A swiveling, or universalling type 
of shackle, used to connect the transverse spring .to the 
side springs of a three-quarter platform suspension; also 
used to connect any two springs lying at 90° to each other 
and in different planes. 

Bead. An indentation in the leaf of a spring which raises a 
portion of the metal on one side and depresses it on the 
other. ■" The successive beads usually "nest" in one another 
and are used in place of the center bolt to prevent trans- 
verse motion of the spring and the separate leaves rela- 
tive to the axle; also used in saw and bead construction 
for alignment. 

Synonyms — Nib, teat, projections, dowels, depressions. 

Beetle Rivets. A special form of rivet used to rigidly connect 
the master leaf and long plate, in a transverse direction, but 
free to slide in a longitudinal one. 

Berlin Head. A head forged on or welded to the end of the 
master leaf in such a manner that a line drawn though the 
center of the head passes through and coincides with the 
center thickness of the master leaf. See Figure 15. 
Synonym — English head. 

Berlin Eye. An eye of a spring plate so formed that a line 
passing though the center of thickness of the master leaf 
passes through the center of the eye. See Figure 6. 

Black-Finish. When the more flocculent scale is removed by 
any one of several methods, there still remains a dark- 
ened oxidized surface on the plates, hence the term. 
Heavy springs are usually finished in this manner. 

Body Springs. A term used to describe the long semi-elliptic 
springs extending from front to rear axle and supporting 
the body and mechanism. The term is now used by some 
in a more general sense to describe the plate springs used 
to suspend the chassis, hence they are sometimes also called 
Chassis Springs. 
Synonym — Side springs. 

Bolt. The word is seldom used alone, but is compounded with 
such terms as : Center, meaning that such bolts are used 

67 



to clamp the leaves together ; End, when used in the eye 
of the spring; Shackle, when placed through shackle and 
eyes; Eye, Spring, Oil Cup, Grease Cup, Self -lubricating. 
The last terms are applied to a shackle, or eye, bolt having 
a grease cup and cap at one end to feed either grease or 
other lubricant to the spring bushings. 

Bolted Rebound Clip. A clip, bolted and riveted to a spring and 
used to prevent the plates from parting with each other 
when the load is suddenly removed from the spring; for 
example, as in a violent rebound. The clips are, usually, 
riveted to one plate and their free ends are connected by 
a bolt and nut. When a tube of brass or steel is placed over 
the bolt in a manner so as to> act as a spacer to prevent the 
clip stock from pinching the sides of the plates this tube is 
specified by adding to the above term "and tube." See 
Figure 14. 

Box Eye. An eye formed on the end of a plate spring produc- 
ing an opening which is substantially rectangular in shape. 
Synonyms — Loop end, box end. 

Box Clip. A U shaped piece of steel having its free ends 
threaded; used to clamp the spring to its seat; usually 
made of verv low carbon steel, but should be made of 
nickel steel. 

Synonyms — Saddle clips, spring clip, seat clip. 

Bright-Finish. When spring plates are ground so as to leave 
the surface bright and without scale. 

Buffer Spring. (See Auxiliary.) The term buffer is also dis- 
torted sometimes to the word "bumper." The word bumper 
when used alone refers to a rubber cushioning device used 
to prevent the striking of such adjacent parts as frame and 
axles. 

Bushing. A hollow cylinder of metal made of steel or bronze 
and used to line the eye of a spring to prevent wear on 
the bolt and eye. 
Synonyms — Sleeve, tube, lining. 

Butt End. See Band. 

68 



Butt of Spring. The thickest portion of the spring; the cen- 
tral portion of a spring where the leaves have not been 
thinned down by tapering or drawing. 

Button Head. A head forged on the end of the master leaf and 
circular in section. The upper surface of the master leaf 
is tangent to the outer portion of the head. See Figure 15. 

Camber. See Arch. 

Cantilever Spring. Another name for a quarter elliptic spring. 
When the thickest portion or butt is fixed to a bracket it 
is called a Fixed Cantilever Spring; when the spring is a 
semi-elliptic spring and so arranged that the center, or 
butt portion, is allowed to swing on the frame or a bracket 
on the car and one end is shackled or otherwise at- 
tached to the frame while the free end is on the axle, then 
the spring is called a Floating Cantilever Spring. When 
one end of a spring has a scroll end, but in other respects 
complies with the general description of the floating can- 
tilever spring it is then called a Floating Cantilever Scroll 
Spring. 

Capacity. The number of pounds required to deflect a spring, 
or combination of springs, one inch. 

Synonyms — Stiffness, scale. 

The word capacity had been used to indicate the total 
load a spring, or system of springs, can carry safely with- 
out taking a set. In this sense it is but rarely used in the 
automobile spring industry. In the railroad leaf spring in- 
dustry the term capacity is used to designate the load the 
springs are designed to carry. 

Cee Spring. Used in England to denote a scroll spring. The 
name C spring is still used in the horse-drawn vehicle spring 
industry to describe a large multiple plate scroll closely 
resembling the letter "C." The true C spring has been 
used by some foreign automobile makers for town car 
suspensions and electric pleasure vehicles. 

Centre Bolt. A bolt used to clamp the leaves of a spring at the 
butt of the spring. 

Check Spring. See Auxiliary. 

69 



Clearance. The vertical height between the two most adjacent 
members in a car when loaded which are liable to strike 
each other. A dimension effecting the design of springs 
with reference to their flexibility and deflection. 
Colloquialism — Jam space. 

Clevis Shackle. A link which is approximately U shaped and 
so arranged that a pin or bolt can be placed through the 
free ends connecting the spring thereto. The lower end 
of the shackle is attached to the vehicle by means of an- 
other bolt. A Loose Clevis Shackle, or universal shackle, 
is used on large three-quarter platform springs to join the 
sides and transverse member. 

Clip Rivet. A rivet used to firmly connect the rebound clips to 
the tapered end of the plates. 

Compass. See Arch. 

Concave Steel. The cross section of spring plate steel is not rec- 
tangular, but is slightly concave at the middle ; the section is 
rolled concave, hence the name. In the earlier davs of the 
spring industry the plates were made concave by ham- 
mering and this operation of concaving the steel was called 
"middling," and the steel was said to have been "middled." 

Constant. A dimension in a three-quarter elliptic spring meas- 
ured from the center of the front end eye of the lower half 
elliptic to the under portion of the master leaf of the quar- 
ter elliptic. A term applied by Mr. William H. Tuthill. 

Cross Spring. The semi-elliptic spring of a platform suspen- 
sion which connects the rear ends of the side springs. 

Curvature. A term applied to the shape of a spring and describ- 
ing its approach to circular shape. 

Dead. When any two or more leaves of a spring placed to- 
gether and not clamped are found to contact along their 
entire length they are said to be dead. (See Nip.) 

Dead Load. A load resting on a spring which does not change 
with time or use. The weight of the body, chassis and 
equipment produce the dead load resting on the springs. 
Synonym — Static Load. 

70 



Deflection. The distance a given point on a spring moves away 
from another and fixed point on same ; usually, the perpen- 
dicular distance traversed by a point in the center of the eye 
relative to a fixed point at the top of the master leaf. A 
displacement of one part with reference to another. A dis- 
tortion. 

Synonyms — Travel, Bending. 

Dimension. Specific lengths, widths and thickness or heights of 
a spring. 

Distortion. Generally applied to the effect produced by the un- 
intentional displacement of the plane of plate, as, for ex- 
ample, in the heat treatment of spring steel, when the 
plates may warp. Unintentional deflection produced by 
extraneous forces. 

Double Scroll. When a scroll is formed at each end of a plate as 
in a double scroll full elliptic spring. A French Double 
Scroll is a full elliptic having a single scroll on each spring 
element. 

Double Sweep. A reversal of curvature in a spring, usually near 
the ends or eyes. Contra-curvature. See Figure 2. 
Synonyms — Reverse Sweep, Reverse Curvature, Double 
Compass ( English ) . 

Dowels. Sometimes applied to a beaded leaf. (More recent 
usage.) A doweled spring is one whose short plate is so 
designed that it has a pin or dowel riveted through a hole 
made for the purpose and into which doweled and coun- 
tersunk head the next beaded plate is inserted. 

Draw. The operation of tapering the leaves of a spring to pro- 
duce points. 
Synonyms — Taper, Scarf, Point. 

When used with reference to heat treatments the word 
draw is synonymous with Tempering or Drawing Doivn. 

Drawn Eye. An eye of a plate spring the leaf of which before 
being rolled into an eye has been tapered. This is some- 
times resorted to in order to maintain an overall diameter 
to a specified dimension. 

71 



Drilled Eye. An eye of a spring whose internal diameter has 
been finished by drilling to specified size. 

Drop. The vertical distance which one end of a spring is lower 
than the other. Front springs generally have a drop. 

Ear. A term used, though not extensively, to describe the eye 
of a spring. 

Egg Shape. Applied to describe the shape of the points of 
leaves. 

Elastic. The property possessed by most materials of returning 
to their original form after they have been subjected to a 
deformation. 

Elastic Limit. When a load is applied to a substance a deform- 
ation, or strain, results ; within certain limits, the result- 
ing strain is directly proportional to the stress ; the point 
at which this proportionality ceases is called the elastic 
limit. When the elastic limit is exceeded the material does 
not return to its original dimension and is said to have 
taken a permanent set. 

Elastic Elongation. The elongation of a material, within the 
elastic limit, due to stresses operating within that limit. 
For good steels the elastic elongation may go as high as 
T 5/10,000 of their length. (See Modulus of Elasticity). 

Elastic Shackle. A term more commonly used by French writ- 
ers, applying to any highly flexible medium interposed 
between two elements of a spring and taking the place of 
the rigid links or shackles. 

Synonym — Supplementary Springs. 

Element. In chemistry, used to denote a material which cannot 
be reduced to a simpler form — such as Gold, Silver, Car- 
bon, Silicon, etc. In spring manufacture it is applied to 
a portion of a spring system which is in itself a completed 
unit ; thus, a three-quarter elliptic spring contains two 
elements composing the spring, the semi-elliptic element 
and the quarter-elliptic element. In a three-quarter plat- 
form we have three elements, the two side elements, and 
the transverse, or cross element. 



Elliptic. A term applied to a spring having the general shape of 
an ellipse. The word elliptic refers in general to a full 
elliptic spring. The modifications are usually designated 
as follows: Full Elliptic, Semi-Elliptic or Half Elliptic, 
etc. 

Scroll Elliptic. An elliptic spring having a scroll at one 
end, this may be a three-quarter or a full elliptic type, 
single or double scroll type, quarter elliptic, or any other 
variety to suit specific cases. 

End. The eye or .other portion most remote from the center or 
butt of the spring. When the end having the eye is referred 
to it is designated as the eye end; also, when a spring is 
offset or eccentrated we have two ends, known as long 
end and short end or, when referring to their relation with 
reference to the car, or vehicle, we speak of them as 
front end and rear end. The eye end is sometimes spoken 
of as the pin end; this term is becoming obsolete in the 
automobile spring industry. When the end of a spring is 
flat and has no eye or, is very slightly curved, the curvature 
being reversed from the general direction of curvature of 
the main plate, the end is then called a plain end. If the 
reverse curvature is very pronounced and has no eye it is 
called a curved plain end; and when, as is sometimes the 
case, the eye of a spring may be drilled and tapped for 
a grease cup, it is called the tapped end. When the master 
leaf is rolled so as to leave a substantially rectangular 
opening or eye, it is called a loop end or box end. The 
leaves may, for one reason or other, be tapered at the 
end ; we then have a tapered end. There are other desig- 
nations for ends, but they are so numerous and but little 
used that they are left out of consideration here. 

Endurance. Applied in the usual lay sense to materials that 
withstand considerable use before destruction. 

English Eye. See Berlin Eye. 

Eccentrate. Eccentric, not central. A spring whose center bolt, 
or butt center, is not in the geometric center of length of 
the spring; this term is best suited to describe this condi- 



tion and we urgently request its use instead of the present 
Synonyms — Offset, Out of Center. 

Eyes. An annular hole in the master leaf of a spring made by 
rolling the leaf back on itself. A pin or shackle bolt is 
used to connect the spring through the eye to its attached 
member on the car. 

The eye of a spring may be turned "up" or "down" or it 
may partake of the nature of both and is then called a 
"Berlin" Eye, or an "English" Eye. 

When eyes are finished by having a bushing inserted, we 
have a "Bushed" Eye. Reamed, Drilled, Solid, Welded 
are explanatory of each type. 

When the outermost portion of the spring eye is "finished" 
to an "exact" width we have a "Milled" Eye. Then we 
have a Swedged, Wrapped, Forged, Rolled and Taper 
Rolled Eye. 

Fillister Head. Refers to shape of the head of the center bolt 
clamping the spring leaves. 

Finish. Used in conjunction with other words describing the 
surface or method used to clean the plates of flocculent 
scale. Thus we have, Bright Finish, Half Bright, Black, 
Grindstone, Polished Top, Buff, etc. 

Flash. Many spring makers to-day and, especially those of old, 
practised a method of annealing the spring plates by in- 
serting them in an oven and waiting until their greasy 
surface became hot enough to flash off the oil hence, the 
term applies to an ancient practice which has been super- 
seded by pyrometers and more exact methods. "Flashed 
Springs" are still too common. 

Flat Top. The portion of a quarter elliptic spring element whose 
length is flat to permit of its being clamped to a flat seat 
or bracket. The amount of flat top (length) is of great 
importance to the spring designer and the car constructor. 
Should be specified on drawings. 

Flexibility. The deflection of a spring in inches per 100 pound 
load placed at its "center." For quarter elliptic springs 
it is the deflection in inches per 50 pounds placed at the 

74 



eye end of the element. In three-quarter platform springs 
the flexibility is the deflection, in inches per 200 pounds, 
placed on the entire system. 

Floating Cantilever. See Cantilever. 

Floating Upper Elliptic. Another term for a floating canti- 
lever spring when used in conjunction with a semi-elliptic 
element at the bottom. 

Floating Upper Scroll Elliptic. The same as a floating upper 
elliptic, except that one end has a scroll. 

Forged Eyes. See Eyes. 

Fracture. A noun used to designate the broken ends of a piece 
of material. The physical aspects of a fracture are usually 
stated thus : Crystalline, Granular, Radial, etc. 

French Points. See Text for photograph. 

Front End. See End. 

Grading. Making the thicknesses of steel used in a spring ele- 
ment variable. The more graded the spring the better, 
but there are limits. 

Grasshopper. A term nearly obsolete, used to describe a semi- 
elliptic spring. 

Grindstone Finish. A colloquialism used by a few spring manu- 
facturers. (See Finish.) 

Half Bright. The "finish 7 ' of the spring leaves. (See Finish.) 

Half Elliptic. See Elliptic. 

Hanger. A misnomer for shackle — more often used to describe 
the brackets or appliances used to connect the shackle with 
chassis. 

Head. The head of a spring is usually a wrought iron forging 
having a variety of shapes which are forged, or welded, 
to the master leaf. (See Berlin Head, etc.) 

Heat Treatment. A process, or several processes, of subjecting 
the materials used in making springs to definite tempera- 
tures or, otherwise acting on these materials through heat- 
ing and cooling to refine and improve their strength and 
endurance; essentially, a careful and precise heating and 



cooling process subject to man}- alterations that endows 
any given material with the best dynamic properties. The 
older spring makers knew little of the scientific aspects 
i )f heat treatment. 

Height. See Camber, Arch, etc. 

Helical Spring. A helical spring is one which is wound on a 
cylindrical surface and the separate turns advance like 
the thread of a screw. These springs may be made of 
either square, round, rectangular or, indeed, any special 
section of bar. 

Helper. See Auxiliary. 

In to Out (Dimension). The upper surface of the master leaf 
is known as the inner and the lower surface of the short 
plate is known as the outer surface of a spring. In a 
three-quarter elliptic, where the master leaf in the quarter 
element is set on a perch, or pad, and the half elliptic has 
its short plate on a perch it is essential that the combined 
heights of springs be given "from pad to pad." This gives 
the "in to out" dimension of the spring. It is never used 
as descriptive of a dimension of a single spring, but always 
applies to a combination of elementary portions. (See 
Text. ) 

In Dimension. See Camber or Height. The height measured 
vertically from center of eyes (or from the end of plain 
end spring) to top of master leaf. 

Inertia. The inherent property possessed by a substance of re- 
sisting change of state. That is, if at rest, it tends to con- 
tinue at rest and when in motion it tends to a continua- 
tion of this state, unless other forces compel alteration 
of this state. 

Isochronous. To swing over different lengths of arcs in equal 
times; to travel over unequal lengths in equal times. 

Jack Spring. See Auxiliary. The term Jack without the apella- 
tion (of the term spring) was used formerly to describe 
a -mall windlass, or apparatus, used to change the height 
of a body on horse-drawn vehicles. 

Jam Space. A colloquialism meaning the same as Clearance, 
which see. 

76 



Laminated. In the early history of the carriage and railroad 
spring industry the springs were always designated as 
Laminated Springs; the term is still used in place of leaf. 
It has no other meaning than that of ordinary usage which 
designates a thin plate or sheet. 

Lap. The distance that one plate in a spring extends over another 
plate at either end; it is the length of this extension. 

Lapped End. When the end of a leaf, usually the master leaf, 
is sharply bent back on itself to form a bearing surface, 
it is then called a Lapped End. In England it is called a 
Slape End. 

Leaf Spring. A spring composed of a plurality of thin sections 
of material in the form of narrow and comparatively long 
plates, or sheets, usually of steel. 

Leaves. The separate plates comprising a leaf spring. 

Left Hand Spring. A spring placed on the left hand side of a 
vehicle ; this may be either front or rear and is so desig- 
nated. 

Length. The length of a spring is understood to be the projected 
length measured between the centers of the eyes of the 
spring; in a semi-elliptic spring it is the chord of the arc; 
this is sometimes also called the Projected Length, The 
actual length of the arc is called the developed length or, 
in shop parlance, owing to it being a length that the plates 
must be cut to, it is known as the cutting length. The 
cutting length is the actual length of the plates. 

Life. A rather indefinite term used to describe the longevity 
of springs when doing work ; the capability of exercising 
its natural functions. See Anti-fatigue and Endurance. 

Lip. A projection on the edges of the leaf, made by forging, or 
drawing out the metal and then turning it up at right 
angles, to the plate width. Used to prevent relative trans- 
verse motion of the plates. 

Synonym — Lug. (Used instead of the word lip by Eng- 
lish spring makers.) 

77 



Live Load. The actual load to be transferred by the vehicle 
aside from its own weight, as passengers, cargo, merchan- 
dise, etc. The load producing deflection in an endurance 
spring testing machine. 

Synonyms — Paying Load, (In case of Commercial Ve- 
hicle). Passenger Load, in luxury or passenger vehicles. 

Load. The weight carried by a spring. 

Long Plate. The plate next to the master leaf in a leaf spring. 

Long End. In an eccentrated spring the longer "half" measured 
from the center of the center bolt, or center of butt, to 
the center of the eye of the corresponding end. 

Loose Shackle. A shackle made of two links and not integral 
with each other — sometimes, (though not properly ) called 
a loose link shackle. 

Loop End. A box eye on end of spring. See Box Eye. 

Main Plate. The longest plate of a spring ; the back, usually hav- 
ing eyes rolled, or forged, at its ends and through which 
the effort or load is applied to the spring. 
Synonyms — Master Leaf, Back. 

Manganese. A chemical element found in all spring steels. 

Master Leaf. See Main Plate, Back. 

Middled. A term formerly applied by English spring makers to 
substantially rectangular sections of steel which are slight- 
ly concave at the middle of the section. 

Middling. The process of concaving spring steel by hammering 
it to concave shape. A term now nearly obsolete. 

Modulus of Elasticity. Applied to desigante the force that 
would be needed to stretch, or elongate, a material, if such 
were possible, to double its original length ; a coefficient of 
stiffness. Thus: if a piece of steel were, say, ten inches 
long and one inch square in section, it would require a 
force of 28,000,000 pounds to stretch it to a length of 
twenty inches. It is true that no piece of steel can with- 
stand such a prodigious force but, the fact is interesting 
nevertheless and the knowledge of this is of great im- 
portance in the realm of mechanics. This value of 28,- 

78 



000,000 seems to be nearly constant for all spring steels 
and is, generally speaking, independent of their chemical 
composition. 

Moment of Inertia. When applied to a plate of rectangular 
shape, as spring steel, it is a mathematical expression of 
its width, multiplied by the thickness cubed, and the re- 
sult divided by twelve. It is the measure of the body to 
resist forces acting thereon and is independent of the na- 
ture of the substance. 

Moment of Elasticity. The product of the moment of inertia by 
the modulus of elasticity; it represents the actual oppos- 
ing, or resisting, force that a given material presents to 
change of shape within the elastic limit of the material. 

Net Weight. The actual weight supported by a spring not includ- 
ing its own weight. 

Neutral Axis. An imaginary axis through the center thickness 
of a plate where no tension or compression exists ; it is an 
axis of shear. It is also the center of gravity of the 
section. 

Nib. See Bead. 

Nip. A term used, more particularly in England, to indicate the 
height between any two adjacent plates of a spring when 
the leaves are not clamped together but the points of each 
successive plate touch the preceding one. When any two 
successive plates have no nip they are said to be ''dead." 
Synonyms — Set, Pinch, Pull. 

Offset. Not central, out of center, eccentrated. 

Open Head. A head, or forging, welded to the end of the main 
leaf in such a way that, the upper face of the leaf is on 
a line tangent with the top of the head ; it is distinguished 
from a button head by the absence of the circular boss 
which is the conspicuous portion of a button head. In an 
open head the stock between the ears extends to the point 
only on the outside circumference of the eye nearest the 
center of the spring. 

Closed Open Head. This head is the same as an open head, 
except that the stock between the ears extends to the end 
of the head. 

79 



Oval Head. The shape of a special bolt head used in the eves of 
some full elliptic springs, which join the two elements to- 
gether. 

Overall. A dimension applied usually to the outside heights of 
full elliptic, three-quarter elliptic springs, and to the overall 
length of a spring measured to the outside portion of the 

eves. 

Peening. An act of striking plates with a round headed hammer 
to straighten them. A practice that should he deprecated. 

Perch. An expression formerly used for a separate bracket 
which the spring rested on, hut now applied to the pad of 
the axle to which the spring is rigidly attached. 
Synonyms — Seat, Pad. 

Perch Filler. A piece of canvas steeped in linseed oil and white 
lead and placed on the perch to fill out the inequalities and 
permitting the spring to be firmly attached to an otherwise 
uneven surface ; probably first suggested by R. D. Wood- 
ford. 

Pin Head. A round pin attached to the master leaf by forging it 
solid, having its long axis parallel and usually in line with 
the center length of master leaf, which enables the end 
of this to go into a hole in the axle. This method of at- 
tachment prevents torsional stress on the main plate. 

Plain End. The end of the master leaf is in some springs left 
without an eye and such ends are frequently straight or 
flat, although, in some instances, this end is given a slight 
reverse sw T eep. 

Plate. A single leaf of a spring. Depending on their location, 
size, or function ; the various plates are named : Long 
Plate, Master Plate, Master Leaf, Short Plate, Rebound 
Plate, Auxiliary Plate, etc. 

Platform. A combination. of four semi-elliptic springs, arranged 
so that two are on the sides and two are across the vehicle ; 
also, any other combination, similarly disposed, with rela- 
tion to the vehicle. When combinations, other than semi- 
elliptics, are used they receive special names of the type 
of spring to which they belong and the word platform is 
prefixed; three-quarter platform, etc. 

80 



Points. The end of the spring leaves. These arc forged or 

drawn into special shapes and receive names accordingly. 
Thus we have Round, Oval, Egg shape, French, Square, 
etc. 

Polished Top. A style of finish in which the upper surfaces of 
the leaves (those visible to the eye when the spring is 
in place) are ground upon a grindstone and afterward 
polished upon a buffing wheel. 

Pressure Block. A piece of metal or wood, shaped approxi- 
mately to fit four to five inches of the short plate of the 
spring and used as a spring seat when applying a load in 
testing springs for their carrying capacities, etc. 

Pumping. The act of loading and unloading a spring rapidly 
to loosen up scale or to "nest" the plates. 

Pull. See Nip. 

Radial Elliptic. A special arrangement of a full elliptic spring 
in which the lower half elliptic is longer and sometimes 
wider than the upper; one end of the upper element is 
attached by a bolt or shackle to the lower and the other 
end is attached by means of a shackle to an extra plate 
lying over the master leaf of the longer spring. 

Rapping. The act of jarring, shaking or tapping a spring, so as 
to release the friction of the plates, thereby enabling the 
efifects of friction to be noticed (or removed) in testing. 

Rear Spring. Any spring used on the rear end of a vehicle. 

Rebound Clip. A "U" shaped piece of steel rigidly attached to 
one plate and surrounding two or more plates and prevent- 
ing their parting in the event of strong rebound, or, on the 
rapid removal of the load from a leaf spring. There are a 
variety of forms of rebound clips used. 

Rebound Plate. A plate placed over the master leaf of a spring 
and so shaped that it carries a load only when the direc- 
tion is, in sense, opposed to that of the main spring. This 
plate may be as long as the main plate, but is usually 
much shorter. Its utility in the respect mentioned is doubt- 
ful, but it possesses other features that are thought de- 
sirable. 

81 



Released Load. The various dimensions of a spring can be 
ascertained by applying given loads, in steps, and measur- 
ing successively their alteration; also a much greater load 
may be applied and by slowly releasing, in steps, the vari- 
ous dimensions can be obtained. The two methods do 
not give the same results, but the last method is some- 
times Used and is called the Released Load Method. When 
used in conjunction with the applied load method it en- 
ables us to ascertain the frictional work of the spring. 

Rib. A long and narrow grooved projection thrown tip 1))- forc- 
ing out metal at the center of leaf point or end, and used 
to align plates. 

Ribbed Spring. A spring whose plates are provided with ribs 
to align the plates. 

Riding Quality. An indefinite term expressing a general but 
vague meaning referring to the softness of a suspension. 

Right Hand. Referring to a spring placed on the right side of a 

vehicle. ( See Left Hand. ) 
Round Head Rivet. A type of rivet having a round head and 

used to fasten the rebound clips to leaf points. 

Rolled. Idie process of making steel plates, or leaves, or the 
points thereon by being passed through rollers. Also 
descriptive of making the eye of a spring. 

Round Point. The shape of the end of a leaf on a spring. No 
precise description can be given to cover this term. (See 
Text.) 

Saddle Clip. Sometimes, but incorrectly, applied to the re- 
bound clip, but more frequently and appropriately applied 
to the box clip used to hold the spring to its seat. 
Synonym — Box Clip. 

Saw and Bead. A means of keeping the plates in alignment. 
A bead or projection is stamped on one plate and made 
to fit into a sawed slot in the adjacent plate. 

Scale. This term is synonymous with the word capacity, which 
see. 

Scarfing". The process of tapering plates to weld on eyes; the 
process of making points on plate ends. 

82 



Scragging. A term used by English spring makers to describe 
a bending test on steel for springs or, a deflection test 
of a spring. 

Scroll End. The end of a spring turned or bent around a form 
giving it a large curve, which is called a scroll. Sometimes 
called a "C" end, owing to the slight resemblance to this 
letter. The term "C spring" is applied by some to a scroll 
end, but this is incorrect. 

Seat. A pad or bracket on which the spring rests. 
Synonyms — Perch, Chair, Pad, Spring Rest. 

Self-lubricating Bolt. A bolt containing a reservoir for grease 
or oil ; the lubricant flows through proper channels to the 
spring eye, or bushing, and, of necessity, lubricates both 
bolt and bushing automatically. 

Self-lubricating Bushing. A bushing containing graphite fillers, 
which are supposed to perform the office of automatically 
lubricating both bushing and bolt. 

Self-lubricating Shackle. A shackle so designed as to contain 
a well or reservoir, together with a proper arrangement 
of wicks to feed oil to the shackle bolts and spring eyes. 
Such are. the F. J. M. or Miesse Shackles. 

Semi-elliptic. A half elliptic spring or, a spring having a shape 
which is approximately a half of an ellipse. 

Set. Meaning the arch or camber of a spring or a plate; in 
this sense the term is not often used. The distance or 
"nip" in respective plates when free and unbolted or un- 
handed and the points of each leaf just contacting with 
the one above it ; a deformation or distortion which has 
become permanent, as in a piece of steel which has been 
stressed beyond its elastic limit. The set is then said to 
be permanent. 

Shackle or Shackel. A clevis or a "U" shaped piece of ma- 
terial used to join a spring to its hangers. 

Shape. Refers to the form or the contour of a spring when 
either free or loaded ; also, the kind of points on a leaf. 

Shock Absorbing. The capacity of a spring to yield to sudden 
blows and prevent their reaching the vehicle. Something 

83 



that prevents rapid or large changes in acceleration by 
being interposed between the substance tending to undergo 

changes of acceleration and the force producing it. 

Short Plate. The shortest plate in a leaf spring forming a unit 

with the scries carrying the main load. 

Side Spring. Any spring used on a vehicle and placed parallel 
to the vehicle length. Formerly this term applied to a 
long semi-elliptic spring extending from the front axle 

to the rear axle and called a Body Spring. 

Silicon. A chemical element. 

Slape End. A spring end having it-- master leaf folded hack on 
itself for a distance of about 2" to 5" and forming a pad, 
or >hoe, to slide on a casting provided for the purpose on 
the frame of the vehicle. 

Sleeve. A bushing usually of metal. A tube. The term bush- 
ing is preferred. 

Soft Spring. A term used to designate a spring having a high 
flexibility. It hears no relation to the quality of steel, for 
all steels are equally "soft" or "hard." See Modulus of 
Elasticity. 

Spacer Clip Plate. A plate placed on the master leaf of the 
spring and used as a distance piece for the box clips. 

Special Bead. A nib or projection in a plate made in accordance 
with some "special" design, the size of the bead not being 
a "standard" carried in stock. 

Special Bolt. The term is clearly indicative. 

Special Bolt Head. This is clearly indicative. 

Specification. A concise and detailed description in writing, or 
a drawing showing the requirements of the purchaser. 
( See Text.) 

Spiral Spring. A spiral spring is one which is wound around 
a fixed center and continually recedes from it like the 
hair spring of a watch; such springs have been recently 
used in conjunction with plate or leaf springs, both in this 
O »unti v and abroad. 

Spoon End. An end on a spring (seldom used now) having 
a concave seat in which a swiveling member fits. 

si 



Spring Hanger (or Horn). A bracket-like piece, permanently 
attached to the frame by rivets or, other Fastening and to 

which the springs are attached by shackles. 

Spring Bracket. Used for the same general purpose as a spring 

horn. 

Spring Leaf Retainer. A longer term, meaning the same as 
a rebound clip. Probably called retainer for it, doubt- 
less partly functions in the same way as a lip or slot and 
bead, saw and bead, etc. 

Spring Stop. A rubber bumper that prevents the spring con- 
tacting with frame or other adjacent members. 

Static Load. The load on a spring which does not alter, as 
frame, body, etc. 

Stiffness. The number of pounds required to deflect a spring, 
or a combination of spring elements made into a unit, one 
inch. 

Synonyms — Capacity, Scale. 

Strain. The stretch or elongation caused by a force or load 
acting on a piece of material. Every stress is accom- 
panied by a strain. Hence^ without a stress there can be 
no strain. Strains produced by forces acting within the 
material are known as internal strains. 

Stress. That which produces a strain. A force. 

Stubbs Gauge. A gauge for measuring thickness used in the 
spring industry. (See Text.) 

Supple. Pliable, yielding, flexible. 

Supplementary Spring. An extra spring of any kind, although 
generally of the helical variety, connected with the plate 
spring and used to increase the total deflection of the 
spring system; sometimes used in the sense of auxiliary, 
helper, or jack springs. The application of this term is, 
for the present, at least, not precise and care should be 
exercised in its application ; it is, indeed, used in two 
distinct and almost opposite senses. 

85 



Snubbing. The process of rolling whereby the thickness of the 
steel is reduced at a given location only. This distin- 
guishes Snubbing from Taper Rolling, in which the thick- 
ness uniformly decreases throughout the length of the 
portion rolled. 

Swedged. The operation of compressing a piece of a plate to 

contract it. as by rolling or otherwise working it. 

Sweep. The radius of the curve to which a spring plate is 
shaped ; a curved line ; also means the arch, or camber, 
or compass. True Sweep, generated by being drawn from 
a single center. Double Sweep; Reversed Sweep, two 
curves drawn from opposite and even different centers, 
producing contra-flexure shapes. Also called Double 
Compass. Varying Sweep, having two or more loci for 
generating curves. 

Synchronism. To be in phase with, to coincide with. 
Taper. To thin down as by rolling, drawing or forging. 

Teat. A nib or projection on a leaf of a specific size. 

Teeter. A colloquialism, meaning to rock like a see-saw, more 
especially used to describe a transverse rolling or rocking, 
as is common in a three-quarter platform suspension using 
a flexible cross spring, or, where a stiffer spring is used 
and a high center of gravity maintained. 
Synonym — Rolling. Rolling or teetering is noticeable 
where the side springs are narrow or where lateral stability 
is wanting. 

Temper. To harden a piece of steel hy heating to a high tem- 
perature, then quenching in a cold medium, as water, oil, 
etc. 

Tensile Strength. The force, measured in pound units, required 

to disrupt a piece of material by being stretched or pulled 
apart. Tensile Strength i*> becoming to be understood as 
the force in pounds required to pull apart one square 

inch i >f material. 

Tensioning. A term Formerly applied to the act of putting a 
nip in plates by peening them. A practice rapidly be- 
coming obsolete. 

96 



Test Height. The opening, camber, or in to out dimension of a 

spring when under a given test load. 

Tobin Bronze. A material often used for bushings in spring 
eyes and consisting substantially of 58.%% copper, 2.3% 

tin and 39.5% zine. 

Transverse Spring. A spring, usually of the semi-elliptic type, 

placed at right angles to the ear length or parallel to the 
car width, and not used in conjunction with any other 
spring. 

Treatment of Steel. Usually applied to abbreviate the term 
heat treatment, which see. 

Torsional Strain. A strain produced by twisting, as the strain 
produced in a shaft transmitting power. Should be 
avoided in springs. Torsional strains are sometimes pro- 
duced in three-quarter elliptic springs when the upper and 
low r er elements are not parallel. 
Synonym — Twisting strain. 

True Sweep. See Sweep. 

Tube Spacer. A brass or, sometimes, a steel tube used to space 
the rebound clips so that they do not bind or pinch the 
plates. 

Twisting Strain. See Torsion. 

Uniform Strength. A spring so proportioned that the stress 
is everywhere the same ; hence, it is of uniform strength. 

Universal Shackle. A shackle or, a combination of two shackles, 
allowing freedom of motion in two planes. 

Underslung Spring. A spring fastened underneath the axle 

instead of on the top of same. 
Vanadium Steel. A steel alloyed with the element vanadium. 

Also applied to a steel in which vanadium may have been 

used during its manufacture to divest it of objectional 

substances. 

Warping. To twist out of intended shape, to distort, as by 
heating or rapid cooling. 

87 



Weight Capacity. The maximum weight a spring will carry 

without permanent set. 

Wrapper. A leaf rolled over the outer portion of the spring eye. 

Wrought Shackle. A shackle made by a forging process from 
wrought iron. 

Yield Point. In testing the strength of materials that point, at 
which, the rate of stretch suddenly increases rapidly. It 

is nearly, but not quite exactly, coincident with the "elas- 
tic limit." Practically the elastic limit is taken as the 
yield point. 



B8 



INDEX 



A Page 

Adams, William Bridges, quoted historically 1 

Additional dimensions necessary on plain end spring 45 

Adjacent Parts, striking 44 

Alinement 9 

Alloy Steels, best composition not agreed upon [5 

Alloy Steels, elements other than carbon in their composition 15 

Alloy Steels, extolling the virtues of 15 

Alloy Steels, greater resistance to fatigue of 16 

Alloy Steels, hardier material 16 

Alloy Steels, increased endurance of 16 

Alloy Steels, increased longevity 16 

Alloy Steel, increase of elastic limit in 23 

Alloy Steels, replacing carbon springs 15 

Alloy Steels, resist fatigue 24 

Alloy Steels, ride exactly as carbon springs 15 

Allo}^ Steels, silico-manganese 24 

Alloy Steels, supposed effect in improving riding qualities 15 

Alloy Steels, with chromium, nickel and tungsten 15 

Alloy Steels, with silicon and manganese 15 

Analysis of Loads 37 

Anti-fatigue, remarkable properties in alloy steels 24 

Appearance of Spring, effected by height 50 

Arbitrary Loads, and riding qualities, relation between 53 

Arbitrary Loads and stress, relation between 53 

Arbitrary Loads, not to be specified 53 

Assembly Prints, checking them with test springs 37 

Axles, their weight not carried on springs 32 

B 

Bead and Saw 10 

Bead, special 7 

Bearing Pressures, in end bolts 7 

Bending, a bar or plate 18 

Bending, back and forth of the leaves of a spring 18 

Bending, of a pencil eraser, examination of 19 

Bending, produces stretching and compressing of fibres 18 

Bent pencil eraser subject to the same laws as a spring 19 

Berlin Head 11 

Berlin Eye 6 

Better grading, Sheldon practice. 17 

Birmingham or Stubbs Gauge, their values in decimals of an inch.. 16 

Block, pressure, for holding spring at center 48 

Bolt, center, details 7 

Bolt, eye 7 

89 



Page 

Bolted Clip 12 

Bolts, shackle 5 

Box Clips, defined 4 7 

Box Clips, diameter of 47 

Box Clips, must be kept tight 49 

I brackets, clearance of and 1 >ther parts 44 

Breakage, caused by seat nor level 49 

Breakage, due to faulty spring seat 47 

Breakage, due to loose fastenings 47 

Breakage, due to ribs n 

Bronze, Phosphor 5 

Br< >nze, Tobin 5 

Bumper 53 

Bumper, effect of, on riding qualities 53 

Bumper, effect ^\, on stiffness 53 

Bushings 5 

Rushing, outside diameter, need not be given 44 

Button 1 lead n 

C 

Cambers, how measured 31 

Car, leveling of, during test 37 

Car Frame, made to tit spring 50 

Car Weight, method of obtaining 34 

Car Weight, typical case of, in detail 35 

Carbon, added to iron, changes its characteristics 13 

Carbon, added to wrought iron changes it to an elastic material.... 13 

Carbon, converts wrought iron into steel 13 

Carbon Steel, not adequate for motor car use 15 

Carrying Full Rated Loads, given on drawing 43 

Center Bolt, details 7 

(.'enter Bolt, location of 8 

Chromium, in alloy steel IS 

Clark expounds mechanics of springs 1 

Class of Service, spring intended for 4."> 

Class of spring service 45 

Clearance, and bumpers, relation between .">:'> 

Clearance, brackets and other parts 44 

Clearance, cut down by bumpers 53 

Clearance, defined .• 53 

Clearance, distance suspended part may he lowered beyond loaded 

position until any two adjacent parts strike 44 

Clearance, give amount of 44 

Clearance, it^ effect <>n riding qualities •">•"> 

Clearance, its effect on stiffness .">:; 

Clearance, of mud guards 1 1 

Clearance, parts underneath car 4 1 

Clinch Clip 12 

90 



Page 

Clips, advantages of 1 % 

Clips, box, defined 47 

Clips, box, diameters of 47 

Clips, loose, effect of 4; 

Clips, necessary for recoil 12 

Clips, necessary when springs take driving effort 4!) 

Clips, special 12 

Clips, use of, in rebound 12 

Closed Open Head 11 

Comfort and Ease of Riding, importance of 18 

Comparison of Leaf Springs, proper 18 

Correspondence, desire to avoid 3 

Cort introduces rolling of steel 2 

Cost effected by clearance 53 

Cost of high springs 51 

Cross Spring Load, not required in ordering complete suspension.. 45 

Cross Spring Load, required when specified without the sides 45 

Cross Springs, action of, intimately connected with side springs.... 45 

Cross Spring, of a platform rear suspension 45 

Cross Springs, stresses may become high 45 

Curvature decreased under load 20 

Curvature, reversed 4 

Curvature uniform, see True Sweep 4 

D 

Dampening of Oscillations, in double sweep springs 4 

Dead Weights 32, 35 

Deflection, amount necessary in a spring 22 

Deflection and Load, relation between 52 

Deflection and Load relation do not hold indefinitely 23 

Deflection, excessive, stopped by bumpers 53 

Deflection, expression for, by Henderson 1 

Deflection, expression for, by Reauleaux. 1 

Deflection, factor influences stress 22 

Deflection, fixed by riding qualities. . 22 

Deflection, free to loaded height determines the riding qualities.... 24 

Deflection of a Spring, dependent on weight of car IS 

Deflection of a Spring, when placed in position on a car 18 

Deflection, other dimensions chosen to give necessary. . , 22 

Design of Cross Springs, at the same time with sides 45 

Details, spring (see part III) 4 

Details to be included in specifications 43 

Diameter of box clips 47 

Diameter of Bushing, outside, need not be given ■ ■ 44 

Diameter of center bolt 7 

Diameter of Eye, show inside dimension 44 

Diameter Outside of Eye, given when limited for room - 44 

Difficulty, due to varying dimensions 

91 



o 



Page 

Dimensions, Additional, required on a plain end spring 45 

Dimensions Shown, at which Springs carry their load 44 

Dimensions, varying, responsible for difficulty 3 

Disadvantages of Stubbs gauge numbers 17 

Distance Adjacent Parts may be lowered from loaded height hefore 

striking 44 

Distance, Horizontal, of center bolts to he given 46 

Distribution of load 32 

Distribution of passenger load 53 

Double Scroll, full elliptic, specification No. 3 59,60 

Double Scroll, Full Elliptic Springs 46 

I )< >uble Sw eep 4 

Double Sweep Springs, weight of 5 

Doubling Load doubles deflection 23 

Downward Weight, in testing springs 39 

1 )ragon Brand, material used in Sheldon Carbon Springs 15 

1 Jraw, of leaves, defined 8 

Drawing, checking up of 43 

I )ra wing, list of items on same 43 

Drawing, load should be given on same when car is carrying its full 

rated load 43 

Drawing, of leaves 8 

Drawing Outline of spring, except top leaf 43 

Drawings, preparation of, and blue print 42 

Driving Effort, taken by spring, precautions 12,49 

I )rop, difference in height 44 

Duck, use of, in spring seat packing 48 

Dudley, Dr. Chas. P., begins investigation of spring steels 2, 13 

Durability, tested by machine 2 

E 

Edgeworth, Dr. R. Lovell, first demonstrates advantages of springs.. 1 

Efficient Distribution, due to better grading 17 

Effort, driving, taken through spring 12, 49 

Egg-shaped point 9 

Elasticity, Modulus of, practically the same in all steels 6 

Elastic Limit, and stress 23 

Elastic Limit, increase of in alloy steels 23 

Elastic Urn it. of carbon spring steel 2.". 

Elastic Limit, of silico-manganese steel 24 

Elastic Limit, of structural steel 33 

Elastic Limit, of wrought iron 23 

Elastic Limit, reached by material 23 

Electric Furnace, introduction of 2 

Electric Furnace Steel 24 

Elliot, Obadiah, obtains an early patent on elliptic springs 1 

End, front of a car, how to get its weight 32, 34 

End, rear, of a car, how t« > get its weight 34 

92 



Page 

End, Plain, spring with 45 

Endurance Testing Machine, first suggested 2 

Enduring in Service, also proper riding IS 

Experimental Model, weight of, on springs 34 

Eye Diameter, show inside dimension of 44 

Eye, Outside Diameter, given when limited for room 44 

Eye, reaming of 5 

Eyes, Berlin 5 

Eyes, height of, measured horizontally 44 

Eyes, lowered under load 29 

Eyes, turned up or down 5 

F 

Face of Spring 40 

Factors, influencing length and width 25 

Failure, caused by lack of load data 32 

Fastenings 47 

Fatigue, due to bending 18 

Faulty Specification .' 28 

P'aulty Spring Seat 47 

Felton, William, author in early spring literature. . 1 

Figures, legibility, on prints 42 

Firm Name, place on print 43 

Firm Name, to identify prints 43 

Flat Springs, look better 50 

Flat Springs, necessary when spring takes driving effort 49 

Flat Springs, ride better 50 

Flat Top 50 

Flexibility and Stiffness, how related 53 

Flexibility, defined 53 

Forged Eye 6 

Frame of car made to fit spring 50 

Free Height, together with stiffness not sufficient 53 

Free, the condition defined 29 

Freight Load, must be in place when weighing a car. . 34 

Friction, inaccuracy caused by, in testing 39 

Friction, produced by double sweep 4 

Front End, of a car, how to get its weight 32, 34 

Front End, state which end is 43 

Front Spring, table of lengths 25 

Front Spring, table of loads 25 

Front Spring, table of widths 25 

Front Spring, where used 45 

Full Elliptic, double scroll spring 46 

Full Elliptic , opening 46 

Full Elliptic, specification 46 

Full Elliptic Springs, table of 26 

Full Elliptic Springs, table of lengths 26 

93 



Page 

Full Elliptic Springs, table of loads 26 

Full Elliptic Springs, tabic of widths 26 

Full Thick, long plate 8 

Furnace, Electric 2 

G 

Gauge Numbers, determined by chance it 

Gauge Numbers, difference between 16 

Gauge, Stubbs or Birmingham, their values in decimals of an inch.. 16 

Geometric Configuration, stresses determined by 2:2 

Glossary of Terms used in the Automobile Spring Industry 65-68 

H 

Half-Elliptic Spring defined 4 

1 1 eads, various types ] 1 

Heat Treatment, depending on nature of material 24 

Heat Treatment, enables a material to better endure 24 

I [eat Treatment, importance not appreciated 24 

! ! c at Treatment, proper for spring steel 24 

I [eat Treatment, to be the same in all leaves 24 

I I eat Treatment, to bring out best qualities 24 

Height, and length, which correspond to the given load 43 

] 1 eight, at each end 44 

Height, difference, measured from lower to upper eye, parallel to 

spring seat 44 

1 1 eight, dimension to be given when full rated load is in car 43 

I i eight, from spring seat to center line of eyes 43 

II eight. Front Eye, three-quarter elliptic above lower spring seat 

important 45 

I I c ights. how measured 31 

! i eight, inside, defined 31 

I 1 eight, its influence on appearan.ee of spring 51 

I I eight, its influence on riding qualities 51 

1 1 eight, of a spring, during test 37 

( 1 eight, of a spring, its influence on appearance 50 

Height of a Spring, when loaded less than when manufactured.... 10 

1 bight of Eyes, measured horizontally 44 

Height, or Camber 4:5 

Height, outside, defined. . 31 

Height, show the difference in the two ends 44 

Height, Total, three-quarter elliptic to be measured from spring 

seat to spring seat 45, 40 

I 1 eight, variable in all springs 29 

i [eight, when one cud is lower than the other 44 

I [eights, with various loads, how to find them 52 

Henderson, G, R., formula for deflection l 

High Springs weigh more than low springs 51 

Holes, nil, give details 44 

!»4 



Pag: 

Holes, Oil, show location of , I 

Horizontal Distance of center bolts to be given n; 

Horizontal, or level spring seat 44 

I 

Jn to Out, height of a three-quarter elliptic spring Hi 

Inch Thicknesses of Spring Steel, advantages of 17 

Inclination of Shackles 29 

Incomplete Information, laboring in the darkness due to 18 

Increased Load injures steel 23 

Indefinitely extended, life 25 

Indirect Methods of obtaining weights on springs :;s 

Influence of Shape on riding qualities 50 

Inspection of Car, opportunity for 18 

Inspection of Car, weighing „ 18 

Inside Height defined 31 

Instructions to Owner, as to box clips 49 

Interpretation and use of spring test sheet 55, 56 

Internal Stress, produced by nipping 1 

Invention of Pyrometer 2 

Invention of Leaf Springs 1 

Investigation of Spring Steels, by Dr. Chas. P. Dudley 13 

Issue letters to identify changes 43 

J 

Jack, screw rack used in getting weights 38, 39 

K 

Kinds of Materials used in plate spring construction 13 

L 

Leaf, master, defined 6 

Leaf, master, takes the driving effort 49 

Leaf Points 8 

Leaf Springs, proper comparisons of 18 

Leaves, number of, should this be specified? 31 

Leaves of a Spring, bent back and forth 18 

Leaves of a Spring, not stationary in service 18 

Leaves, thickness of, should this be specified? 31 

Left Side, weight of . . 33 

Length and Width, closely connected 25 

Length, center to center of eye 43 

Length, factor influencing stress 22 

Length, from eye to center bolt 43 

Length, measured horizontally 43 

Length of Front Springs, table of 25 

Length of Life, dependent on load 32 

Length of Life, second in importance 18 

95 



on 



Page 

Length of Life, to resist wear and destruction 18 

Length of Scroll, where straight, should be specified 50 

Length of Spring, during test 37 

Lengths of Spring, proper, for pleasure cars 25 

Length, partial 43 

Length of springs, choosing of 22 

Length, of spring scat 44 

I ength, of steel and total 43 

Length, proper, to maintain life 

Length, survival of life effected by 

Length, total 4:; 

Length, variable, in all springs 29 

Length, variable, increased when loading 29 

Letters, issued to identify changes 43 

Level, car must stand level when getting loads 34 

Leveling the car during test 37 

Level Spring seats must be obtained 4 ( .) 

Life, and thick leaves not compatible 2:2 

Life, and thin leaves 22 

Life, extended indefinitely 25 

Life, governed by stress 22 

I ife, length of, dependent on load 32 

Life, Length of, secondary importance L8 

Life, maintenance of 22 

Life, of a spring measured by stress in its fibers 19 

Life, proper, for service in question 25 

Life, requirements demanded by long 22 

Li fe, the resistance to wear and destruction IS 

Limit of Elasticity, reached by a material 2.'> 

Lips 11 

Loads, analysis of, in car design 37 

Load and Deflection, effect or. riding quality 16 

Load and 1 >eflection, relation between 52 

1 oad and Deflection, same for all steels i<> 

Load, empty, together with passenger load not sufficient 53 

Load, importance of, in specifications 32 

L« >ad, influence of, on height 29 

L< ad, influence of, on length 29 

Load, lack of knowledge of, introducing difficulties 3 

Load of Freight, must he in place when weighing a car 34 

Load of Front Springs, table of 25 

Load of Passengers, must be in place when weighing a car 34 

I oad on Cl*OSS Spring, not required in ordering complete suspension 4.") 

L'-ad on Cross Spring, required when specified without sides 45 

I. ad on Spring, given to carry at shown dimensions 44 

Loads on Springs, indirect method of obtaining 38 

Load, or spring, rated load in car 44 

91; 



Page 

Load, on spring, state if given load is rated load, or includes a 

percentage of overload a \ 

Loads, their effect judged from the pounds per inch 52 

Longevity, and proper materials 

Longevity, maintenance of 

Long Plate, defined 6 

Long Plate, full thick 

Long Plate, length of, when eye is turned down 6 

Long Springs, may be heavier 25 

Loose Clips, effect of 47 

Loose Fastenings, effect of 47 

Low Springs, look better 51 

Low Springs, ride better . 51 

M 

Manganese, in alloy steels 15 

Master Leaf, defined 6 

Master Leaf, longer in high springs 51 

Master Leaf, secured by clip when taking driving effort 12 

Master Leaf, takes the drivng effort 49 

Material, proper, much to be said regarding same 23 

Materials, used in plate spring construction 13 

Mechanics, of springs, first expounded by Clark 1 

Micro-structure of Steel, first studied 2 

Model, Experimental, weights on springs 34 

Model, Specification, for a semi-elliptic spring 43 

Model Specifications 42 

Modulus of Elasticity practically the same for all steels 6 

Moments, method of, in getting weights 40 

Mud Guards, clearance of 44 

N 

Xib 7 

Nickel, in alloy steels 15 

Nipping, internal stress produced by 1 

Numbered, all prints to be 43 

Number of Leaves, should this be specified ? 31 

O 

Off Center, center bolt 8 

Oil Holes, give details 44 

Oil Holes, show location of 44 

One per cent. Carbon Steel having withstood hard service 15 

On the Floor, length of spring 29 

00, double ought, thickness of steel not used 16 

Open Head 11 

Opening, defined 31 

Opening of Full Elliptic Springs 46 

Order springs in sets 45 

97 



Page 

illation dampened in double sweep springs 4 

'■( hit,*" outside height, defined :;i 

"( hit to Out," height of a three-quarter elliptic spring 4fl 

( Outline Drawing only, except top leal 4:; 

Outside Diameter of Bushing need not be given 44 

Outside Diameter of i\ye. best policy to make it large and strong.. 44 

Outside Diameter of Eye given when limited for room 4t 

Outside Diameter of Eye should usually be left to the spring-maker 44 

Oval Points s 

( Jverslung Spring, height of, how measured 31 

I )\\ ner of car must keep clips tight 19 

P 

Packing, between seat and spring 4S 

Packing, for seat 48 

Partial Length 4:; 

Passenger Load, must be in place when weighing car 34 

Passenger Load, together with load empty not sufficient data 53 

! encil Eraser, examination of, when bent 1§ 

Pencil Eraser, possesses stretching properties to a large degree.... ~1 

Pencil Eraser, when hent, is subject to the same law as a spring.... 19 

I ennsvlvania Railroad, investigations into the merits of carbon steels 13 

Permanently bent, due to overload 23 

Perry, Prof. John, on internal stresses 1 

Phosphor Bronze 5 

Plain haul, additional dimensions necessary 45 

Plain haul, a spring having 45 

Plate, long defined 6 

Plate, short defined 6 

Platform, rear cross spring 45 

Platform Scale used in getting weights 38 

Platform. Springs, specify all at one time 45 

P< »ints 9 

Points, leaf 

Points, rolling of S 

Points, round S 

Poor Riding Springs, not fulfilling mission i s 

Poor Riding Springs, not 10 reject before consultation L8 

Poor Riding Springs, rejection of IS 

Position of Shackles during test 37 

! "imds per Inch, defined 52 

Pounds per Inch, variation in. due to length 52 

Precautions, when driving through the springs 40 

Pressure, bearing in end bolts 7 

Pressure Block, for holding spring at center 48 

Prints, and body facts required 42 

Prints, bona fide, not pencil drawings 42 

Prints, from pencil seldom legible 42 

... 



Pago 

Prints, legibility of figures thereon » 2 

Prints, the car builder should submit ]•: 

Proper Comparisons of leaf springs i > 

Proper Material, much to be said regarding same 23 

Proper Suspension, small details can contribute materially to 18 

Pyrometer, invention and improvement of 2 

R 

Rapping a spring during test, effect of 39 

Rated Full Load, given on drawing 4:5 

Reaming, of eyes 5 

Rear End, how to get its weight 34 

Rear, Semi-Elliptic Springs, lengths, table of 26 

Rear, Semi-Elliptic Springs, loads, table of 26 

Rear, Semi-Elliptic Springs, table of 26 

Rear, Semi-Elliptic Springs, widths, table of 26 

Rear Spring, state where used 45 

Rear, Three-quarter Elliptic Springs, lengths, table of 26 

Rear, Three-quarter Elliptic Springs, loads, table of 26 

Rear, Three-quarter Elliptic Springs, table of 26 

Rear, Three-quarter Elliptic Springs, width, table of 26 

Reauleaux gives expression for stress and deflection 1 

Rebound Clips, necessary when spring takes driving effort 49 

Rebound, use of clips in 12 

Recoil, making clips necessary 12 

Rejection, of poor riding springs 18 

Relation of Deflection, and load does not hold indefinitely 23 

Repeated Bending, no bar can withstand, indefinitely 18 

Restriction of scroll thickness not recommended 50 

Revision, a simple method of noting same on prints 43 

Rib 10 

Riding, judged by stiffness 52 

Riding Qualities, and amount of loads, relation between 53 

Riding Qualities, effected by bumpers 53 

Riding Qualities, effected by clearance 53 

Riding Qualities, influenced by shape 50 

Riding Qualities, not effected by rib 10 

Riding Qualities, supposed effect in improvement of, by use of 

alloy steel 15 

Right Side, weight of 33-35 

Rolling, of points 8 

Rolling of Steel, first introduced by Cort 2 

Round, point 8 

S 

Saw and Bead 10 

Scroll, details to be left to spring designer 46 

Scroll, general size may be given 46 

99 



Page 

Scroll, how tested 50 

Scroll, made to fit frame 50 

• '11. the cursed part of quarter element 46 

Scroll, thickness of, should not he prescribed 50 

Seat, not level, effect of 4'.) 

• oi Spring 4(*> 

Seat of Spring, defined t\ 

Scat of Spring must he level transversely 49 

Seat Packing 4^> 

Seat. Spring, keep horizontal 44 

Seat, Spring, proper design of 47 

:. Spring, shape of 48 

Selecting leaf thickness, by spring designer to give long life 23 

Semi-Elliptic Rear Springs, length, tahle of 

Semi-Elliptic Rear Springs, loads, tahle of 26 

Semi-Elliptic Rear Springs, tahle of 26 

Semi-Elliptic Rear Springs, widths, tahle of 26 

Semi-Elliptic Spring, defined ■ 4 

Semi-Elliptic Spring, specification No. 1 56 

Service, class of spring 45 

Service, severe, in motor car spring 15 

Severe Service, in motor cars 1.") 

Shackle Bolts, should he case hardened 5 

Shackle Position during rest 37 

Shackle Position of under load 29 

Shape, measures stress 22 

Shape, not permanent in double sweep springs 4 

Shape of Spring, effects riding qualities 50 

Shape of Spring, general remarks 50 

Shape of Spring Seat 4S 

Sheldon Axle Co., practice to and thickness of rolling steel 17 

Sheldon Axle Co., spring test and data sheets 55,56 

Short Plate, defined 6 

Short Plate, length of, in high springs 51 

Shon Springs may he hard riding, due to decreasing stress 25 

Short Springs may be stressed too high 25 

Side <>f car. weights of 33 

Side spring, action of, intimately connected with cross springs.... 45 

Side Spring Stress may become high springs 45 

Silico-Manganese, electric furnace steel 24 

Silicon in alloy steel. . . 15 

Sler\ e < iver clip holt 12 

Slot and Bead, South American 9 

Society of English Arts and Manufacturers, awards medals for 

spring development l 

Sorby, Dr., introduces micro-structural studies of steel 2 

South American slot and head 9 

Kin 



Page 

Spacer Block is 

Special Bead 7 

Special Round Point 9 

Specification, a faulty, examined 

Specification, definition of 3 

Specification, model for a semi-elliptic spring 45 

Specification No. 1, semi-elliptic spring 56 

Specification No. 2, three-quarter scroll elliptic 57 

Specification No. 3, double scroll, full elliptic 59, 60 

Specification, three-quarter scroll elliptic 45 

Specifications, foreword in writing 2«s 

Specifications, for leaf springs 42 

Specifications, model 42 

Specifications, preparing a statement of requirements 42 

Specifications, suggestion for the preparation of 42 

Specify whole platform system at one time 45 

Speed and Weight, producing increased shocks and deflections 15 

Spring Design, art of 22 

Spring Designer, choosing length of springs 22 

Spring Designer, selecting thicknesses of leaves to give long life.. 23 

Spring Fastening, by pressure block 49 

Springs in Sets, order 45 

Spring Leaves, bent back and forth 18 

Spring Leaves, not stationary in service 18 

Spring Load, given to carry at shown dimensions 44 

Spring Load, rated load in car 44 

Spring Load, state if given load is rated load, or includes a per- 
centage of overload 44 

Spring makers decision for outside diameter of eye 44 

Spring Seat Faulty, effect of 47 

Spring Seat, give length of 44 

Spring Seat, keep level 44 

Spring Seat, proper design of 47 

Spring Seat, shape of 48 

Spring Simple, deflection varies with load 23 

Spring Steel Specifications 13 

Spring Steel Specifications, standard for vehicle springs 15 

Spring test and data sheets 55, 56 

Spring Tested, conditions same as in service 45 

Spring test sheet, interpretation and use of 55, 56 

Square Point 9 

Steel, containing one per cent, carbon, has been found to be best.. 13 

Steel, contains various percentages of carbon. 13 

Steel, micro-structure of 2 

Steel, regarded as iron which has been converted by the addition 

of carbon 13 

Steel, rolling of, first introduced by Cort 2 

101 



Page 

Stiffness, influenced by clearance 53 

Stiffness, it- effect on riding qualities 

Stiffnes ther with free height not sufficient 53 

Stiffness, variation in. due to length 52 

Straight length of scroll should be specified 50 

Straight springs necessary when spring takes driving effort 40 

Strength of rib 10 

Stn geometric condition 22 

Stress Changes due to ribs l 1 

Stress and length, relation not simple between 21 

Stress, comparison of 19 

Stress, decreases from outer fibers to center :.M 

Stresses, due to restrictions of scroll thickness .">() 

Stress due to tort ion. caused by faulty seat 40 

Stress, t xpression for, by Reauleaux l 

Stress, governs life 22 

Stress in en >ss spring may become high 4.*> 

Stress in side springs may become high 4."> 

Stress, internal, produced by nipping 1 

Stress, measured by shape 21 

Stress, measured on outermost fibers 21 

Stress, measure of 10 

Stress, produced by a pull on libers of a metal 19 

Stresses produced may exceed the elastic limit of the material 16 

Stress, regarding as a deep term 10 

Stress, relation between and dimensions of a spring 10 

Stress, relation between and thickness a simple one 21 

Stress, variation with length 21 

Stress, varies as deflection 21 

Stress varies as thickness of leaf 21 

Stress varies inversely as the length squared 21 

Stubbs, <»r Birmingham Gauge, their values in decimals of an inch.. 16 

Sweep, double 4 

Sweep, true 4 

T 

Table of fronl springs 25 

Table of front spring lengths 25 

Table of front spring loads 25 



Table of fr»nt spring widths .■ 25 

Table of full elliptic springs 26 

Table of full elliptic spring lengths 26 

Table of full elliptic spring loads 

Tabh • f full elliptic spring widths 

Table of rear semi-elliptic springs 

'I able of rear three-quarter elliptic springs 26 

Table of semi-elliptic rear springs 

Table of semi-elliptic rear spring lengths 26 

102 



> 



Pag 

Table of semi-elliptic rear spring loads 26 

Tabic of semi-elliptic rear spring widths 26 

Table of spring lengths 

Table of spring widths 

Table of three-quarter elliptic rear springs 

Table of three-quarter elliptic rear spring lengths 26 

Table of three-quarter elliptic rear spring loads 26 

Table of three-quarter elliptic rear spring widths 20 

Table of three-quarter platform springs ::: 

Table of three-quarter platform spring lengths 2 " 

Table of three-quarter platform spring loads 27 

Table of three-quarter platform spring widths £7 

Tensile Testing Machine, use of, in getting spring data 39 

Tested Spring, under conditions same as in service 45 

Testing Machine, endurance, first introduced 2 

Testing Machine, use of, in getting spring data 39 

The Sheldon Axle Co.'s spring plant and organization 01-04 

Thick Leaf Spring, light spring 24 

Thick Leaves, or thin leaves produce practically the same riding 

qualities 2 + 

Thick Leaves, small number required to support load 24 

Thickness, factor influencing stress 22 

Thickness of Leaves, should this be specified? 31 

Thickness of scroll should not be prescribed 50 

Thickness of spring steel, used in the vehicle spring industry 10 

Thickness of steel greater than § not carried in stock 16 

Thickness, uniform, importance of 1 

Thin Leaf Spring, heavier spring 24 

Thin Leaves, large number is the heavier 24 

Third box clip, recommended 48 

Three box clips, use of, recommended 48 

Three-eighths of an inch thickest section used in carbon spring steel 16 

Three-quarter Elliptic, in to out dimensions 40 

Three-quarter platform springs, lengths, table of 27 

Three-quarter platform springs, loads, table of. 27 

Three-quarter platform springs, table of : 27 

Three-quarter platform springs, widths, table of 27 

Three-quarter Scroll Elliptic, model specification 45 

Three-quarter spring scroll made to fit frame 50 

Tight box clip, box clips must be tight 49 

Tolerances, close, not to be had in early hand-made materials 1 

Torsion due to seat not being level 49 

Total Deflection, proper share of stress in platform elements 45 

Total Deflection, proper shares on cross and sides 45 

Total Deflection, proper share on sides and cross 45 

Transverse motion of leaves 

True Sweep Spring 4 

103 



Page 

Tube, 01 er clip bolt 12 

Tungsten, in alloy steels 15 

'•Turned Dowi 

"Turned Up" eyes 5 

Typical car weights 35 

U 

Underslung spring, height of, how measured 31 

Uniform curvature, see Tru< Sweep 4 

Uniform thickness, importance of I 

Unsprung Weights, how to record 

"Upward" weight in testing springs :;o 

V 

Variable I [eight, in all springs 29 

Variable Length in all springs 29 

W 

Wear in eyes 5 

Wedgewood invents pyrometer 2 

Weight, analysis of, in spring design 37 

Weight downward in testing" springs 39 

Weight, happy mean, designer's skill 25 



N 



589 



«) 



32 



Weight, increase of, goes into increased life 

Weight of axles " 32 

Weight of car. methods of obtaining 34 

Weight i >f car parts, typical case in detail 35 

Weight of double sweep springs 5 

Weight of front end, how to obtain it 34 

W eight of parts not resting on springs 35 

Weight of rear end, how to obtain it 34 

Weight of right side 35 

Weight of spring, relation to life 24 

Weight (^\ wheels not carried on springs 

Weight, dead 

Weight upward in testing springs 39 

Weights, before car is constructed 40 

Weights on Springs, approximate methods of obtaining 38 

Wheels, their weight not carried on springs 32 

Width and length closely connected 25 

Width of front springs, table of 25 

Width, proper for pleasure cars 

\\ rapper o 

Wrought Iron, cannot be easily hardened L3 

Wrought Iron, consi>i> of the element iron in nearly pnre state.... 13 

Wrought Iron, is a comparatively soft and plastic metal 13 

Wrought Iron, physical or thermal treatment does not effect 13 

Wrought Iron, remains a nearly inelastic substance 13 

104 



LIBRARY OF CONGRESS 




013 398 623 6 A 




